JP6819210B2 - Hot water heater - Google Patents

Description

According to the present invention, when the hot water supply is on standby (when the hot water supply is not used), the hot water in the hot water supply path is circulated so as to return to the water supply side to heat and keep warm, so that hot water of a predetermined temperature can be immediately made to be hot water at the next hot water supply use. The present invention relates to a hot water supply device having a heat retaining function, and particularly relates to a technique capable of avoiding an excessively long continuation of combustion operation for heat retaining operation.

Conventionally, a hot water supply device having a heat retaining function for immediate hot water has been known. For example, Patent Document 1 includes a return path that branches from a hot water supply channel located in front of a hot water supply plug and joins the water supply channel, and a circulation pump for returning and circulating hot water through this return path. It is described that the heat retention operation control is performed by operating the circulation pump to burn and heat the circulating hot water.

Further, in Patent Document 2 (see, for example, paragraph 0035), hot water staying in the heat exchanger is targeted, and when the hot water is on standby, the combustion burner is combusted and operated without circulating the hot water in the heat exchanger. It is described that when the heat retention combustion control of heating the retained hot water is performed, the heat retention combustion is automatically stopped when the set time elapses from the time when the combustion for heat retention is started.

Japanese Patent No. 5708975 Japanese Patent No. 30987730

By the way, the piping installed for hot water supply from the water heater to the hot water tap and the piping installed for the return path for heat retention operation may be installed outdoors depending on the installation site, or may be installed over a relatively long distance. It may be done. For this reason, it is easily affected by the outside air temperature due to seasonal fluctuations, and there is a possibility that inconvenience may occur due to an increase in heat dissipation (hereinafter referred to as "pipe heat dissipation") while passing through the pipe. For example, when waiting for hot water supply, the circulation pump operates to return hot water from the hot water supply channel to the water supply channel via the return path, heat it with a combustion burner, and then circulate it in the hot water supply channel. When the temperature drops to the predetermined heat retention operation start temperature, the circulation pump and combustion burner are operated to start the heat retention operation, and when the temperature of the circulating hot water rises to the predetermined heat retention operation stop temperature, the circulation pump and combustion burner are activated. Considering the case where the heat-retaining operation control of stopping the heat-retaining operation is performed, the following inconveniences may occur.

That is, even if the hot water returned from the hot water supply channel is heated by the combustion burner, when the amount of heat radiated by the heat dissipation from the pipe is relatively large, the temperature rise of the circulating hot water becomes slow, and as a result, the combustion burner continues to burn for a long time. Even if the temperature is increased, it is possible that the temperature does not rise to the heat retention operation stop temperature. In this case, the heat retention operation does not stop, and the combustion operation continues until the next use of hot water supply.

The present invention has been made in view of such circumstances, and an object of the present invention is to continue the heat retaining operation for an excessively long time in the heat retaining operation control executed during standby for operation such as hot water supply. The purpose of the present invention is to provide a hot water supply device that can guarantee a heat retaining function based on a heat retaining operation while avoiding the problem.

In the present invention, the heating unit, the circulation path connecting the heating unit and the circulation destination, the circulation pump, and the circulation pump are operated when a predetermined condition is satisfied to circulate the hot water heated by the heating unit. The following specific items are provided for the hot water supply device provided with the heat retention operation control unit for executing the heat retention operation for circulating the circulation between the pump and the circulation path to keep the inside of the circulation path warm. That is, a temperature sensor for detecting the in-passage temperature of hot water in the circulation path is provided, and the heat-retaining operation control unit starts the heat-retaining operation in which the detection path temperature detected by the temperature sensor is preset. The heat retention operation is started when the temperature falls below the temperature, while the heat retention operation is stopped when the temperature in the detection path rises to a temperature equal to or higher than a preset heat retention operation stop temperature by the heat retention operation. If the temperature inside the detection path does not rise above the temperature at which the heat retention operation is stopped even after a predetermined set time has elapsed since the start of the heat retention operation, the temperature inside the detection path at that time of the circulation path is stopped. It shall be the configuration to be updated as temperature.

When this specific item is provided , for example, at the turn of the season when the outside air temperature drops sharply, the heat dissipation of the pipe increases, and most of the heat applied by the combustion in the heating part is lost by the heat radiation of the pipe. Even in an environment where the temperature of the circulating hot water hardly rises no matter how much the circulation based on the heat retention operation is continued, the heating part continuously burns for an excessively long time as the heat retention operation is executed. It is possible to avoid the situation of continuing. That is, if the detection path temperature does not rise to the heat retention operation stop temperature even after the set time elapses, the detection path temperature at that time is newly set as the heat retention operation stop temperature and updated. Therefore, further combustion continuation in the heating part is avoided. In addition, the heat retention operation is repeatedly executed by the heat retention operation control unit, and the heat retention operation stop temperature is updated, so that the temperature is updated by learning according to changes in piping heat dissipation based on environmental factors such as the season at that time. The heat retention operation can be appropriately and effectively performed by using the stop temperature. On the other hand, since it is considered that the temperature in the road drops to the start temperature of the heat retention operation early after the heat retention operation is stopped, the next heat retention operation is started early, so that the heat retention function in the environment can be appropriately ensured. become able to.

Further , in the present invention , an integrating unit for integrating the energizing time to the heat retaining operation control unit is provided, and as the heat retaining operation control unit, the energizing time integrated by the integrating unit represents a change in environmental factors. the maintenance operation stop temperature was be configured to return to the initial set original value for each reaches a predetermined set current time set as (claim 1). By doing so, it is considered that the environmental factor may have changed with the passage of the set energization time, and the heat retention operation stop temperature updated by learning is returned to the initial set value, and again under the current environmental factor. , It becomes possible to determine and update the heat retention operation stop temperature. As a result, even if seasonal fluctuations or changes in the installation environment occur, it is possible to learn the heat retention operation stop temperature according to the environmental factors, and the heat retention operation by the heat retention operation control unit can be appropriately and effectively executed. It will be possible.

The hot water supply device of the present invention may be provided with a release switch for releasing the update content acquired by the heat retention operation control already executed by the heat retention operation control unit (claim 2 ). By doing so, it is possible to cancel and reset the learning and the like by the heat retaining operation control unit by the user's own intention, and it is possible to realize the operation of the hot water supply device according to the user's intention.

Further, in the hot water supply device of the present invention, the circulation destination includes the hot water supply destination, the water supply channel, the heating unit for heat exchange heating the water supplied through the water supply channel by the heat of combustion, and the heating unit. The heat retention operation control unit is provided with a hot water supply path for supplying hot water to the hot water supply destination and a return path for branching from the vicinity of the hot water supply destination and returning the hot water to the water supply channel. When waiting for hot water supply, a circulation pump interposed in the return path may be operated to heat exchange heat the hot water returned through the return path in the heating unit and then discharge the hot water to the hot water supply path ( Claim 3 ). By doing so, the temperature of the hot water in the hot water supply channel to the hot water supply destination is kept at a desired temperature suitable for the hot water supply use when the hot water supply is on standby until the next hot water supply use after the previous hot water supply use is completed. While realizing the immediate hot water function that hot water of a desired temperature can be immediately discharged when the hot water supply is used, it is possible to avoid the occurrence of inconvenience due to the influence of pipe heat dissipation due to environmental factors and the like.

As described above, according to the hot water supply device of the present invention, for example, at the turn of the season when the outside air temperature drops sharply, the heat dissipation of the pipe increases, and most of the heat applied by the combustion in the heating part. However, as a result of the heat being lost due to heat dissipation from the piping, even in an environment where the temperature of the circulating hot water hardly rises no matter how much the circulation based on the heat retention operation is continued, the heating part will be affected by the execution of the heat retention operation. It becomes possible to avoid a situation in which continuous combustion continues for an excessively long time. That is, if the detection path temperature does not rise to the heat retention operation stop temperature even after the set time elapses, the detection path temperature at that time is newly set as the heat retention operation stop temperature and updated. Therefore, it is possible to avoid further combustion continuation in the heating unit. In addition, since the heat retention operation is repeatedly executed by the heat retention operation control unit and the heat retention operation stop temperature is updated, the heat retention updated by learning according to changes in piping heat dissipation based on environmental factors such as the season at that time. It becomes possible to perform the heat retention operation appropriately and effectively by using the operation stop temperature. On the other hand, since it is considered that the temperature in the road drops to the start temperature of the heat retention operation early after the heat retention operation is stopped, the next heat retention operation is started early, and the heat retention function in the environment can be appropriately ensured. ing so. Moreover, assuming that the environmental factors may have changed with the passage of the set energization time, the heat retention operation stop temperature updated by learning is returned to the initial set value, and again under the current environmental factors, the heat retention operation stop temperature. It becomes possible to judge and update. As a result, even if seasonal fluctuations or changes in the installation environment occur, it is possible to learn the heat retention operation stop temperature according to the environmental factors, and the heat retention operation by the heat retention operation control unit can be appropriately and effectively executed. It will be possible.

It is a schematic diagram which shows the example of the hot water supply apparatus which concerns on embodiment of this invention. It is a flowchart which shows the example of the heat retention operation control of a hot water supply device. It is a schematic diagram which shows the other structural example of a hot water supply device. It is a schematic diagram which shows the other structural example of the hot water supply apparatus different from FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows an example of a hot water supply device with an immediate hot water function according to the present invention.

First, the overall configuration of the hot water supply device 1 will be briefly described. The hot water to be heated enters the heat exchanger 21 in the can body 2 through the water supply channel 3, and is heated by heat exchange heating to a predetermined high temperature (for example, maximum 75 ° C.) by the combustion heat of the combustion burner 22 in the heat exchanger 21. After that, the hot water is discharged to the hot water supply channel 4. Next, the temperature of the hot water discharged is adjusted to the set hot water supply temperature by mixing the water from the bypass path 6 in the mixing section 5 on the way, and the hot water after the temperature adjustment is passed through the hot water supply passage 4 and the hot water supply pipe 7 to the hot water tap. Hot water is supplied up to 71. These inflow, outflow and hot water supply are performed based on, for example, the supply pressure from a water pipe connected to the upstream end of the water supply channel 3, the pump water supply pressure from another supply system, and the like. Although only one hot water tap 71 is shown in FIG. 1, it can be installed in a plurality of places such as a bathtub tap and a shower curan in addition to a hot water tap in a kitchen or a washroom. It is configured.

In addition, when waiting for hot water supply (when hot water supply is not used and waiting until hot water supply is used), immediate hot water is used to keep the hot water in the hot water supply passage 4 and the hot water supply pipe 7 at a predetermined temperature in advance. A circulation circuit 8 is provided. That is, the immediate hot water circulation circuit 8 causes the hot water in the hot water supply passage 4 and the hot water supply pipe 7 to flow into the water supply passage 3 by the operation of the circulation pump 81 to return the hot water to the water inlet side of the can body 2 and heat the can body. The immediate hot water function is realized by circulating heating between 2 and the hot water tap 71 side. Reference numeral 30 in the figure is a check valve that prevents backflow to the upstream side of the water supply channel 3, and reference numeral 80 is a check valve that prevents backflow from the water supply channel 3 to the immediate hot water circulation circuit 8 side. Hereinafter, each component will be described in detail.

The can body 2 is a combustion burner 22 that burns by receiving the supply of combustion air from the blower fan 9 and fuel gas from the fuel supply system 23, and a heat exchanger that is heat exchanged and heated by the combustion heat of the combustion burner 22. 21 is built-in. A heating unit is composed of a combustion burner 22 and a heat exchanger 21. The fuel supply system 23 includes a gas supply pipe 230, a source gas solenoid valve 231 and a gas proportional valve 232.

The heat exchanger 21 includes a main heat exchanger 24 for heat exchange heating by the actual heat of combustion gas, and an auxiliary heat exchanger 25 for preheating by recovering latent heat of combustion exhaust gas after passing through the main heat exchanger 24. An example composed of is illustrated. Then, the downstream end of the water supply channel 3 is connected to the inlet of the sub-heat exchanger 25, and after being preheated while passing through the sub-heat exchanger 25, heat exchange heating is performed while passing through the main heat exchanger 24. The heated hot water is discharged to the upstream end of the hot water supply passage 4 connected to the outlet of the main heat exchanger 24.

On the other hand, when the latent heat is recovered by the auxiliary heat exchanger 25, water vapor in the combustion exhaust gas condenses to generate strongly acidic drain. Therefore, this drain is collected by the drain pan 26, for example, in a neutralization treatment tank ( It is designed to be drained after being neutralized (not shown). It should be noted that the fact that the heat exchanger 21 is provided with two types of heat exchangers 24 and 25 and that the heat exchanger 21 is provided with a component 26 for drain treatment is not essential in the present invention and is heated by receiving water supply. The present invention can be applied as long as it is possible. Therefore, the heat exchanger 21 can be configured only by the main heat exchanger 24 described above.

The combustion burner 22 is configured to have a variable combustion amount (variable combustion capacity), whereby the hot water discharge capacity is variable. The combustion burner 22 is composed of, for example, a plurality of combustion nozzles capable of individually supplying fuel by a gas on-off switching valve (capacity switching valve), and each gas on-off switching valve is controlled by the controller 10. By controlling the opening / closing switching, the number of combustion nozzles for combustion operation can be selectively changed and adjusted. The ones in the figure are grouped into two, one, two, four, eight, and four combustion nozzles from the right, and if the capacity switching valve 221 is opened and switched, the two on the right end side of FIG. If the capacity switching valve 222 is opened and switched to the one combustion pipe on the left side, if the capacity switching valve 223 is opened and switched to the two combustion pipes on the left side, and so on. It can be supplied. As a result, the combustion capacity can be switched to 6 stages, for example, 1 to 6 stages. In addition, the amount of combustion can be made variable by making the flow rate of gas supplied to the combustion nozzle of each stage variable. By continuously variable control of the combustion amount as described above, the hot water discharge capacity, that is, the hot water discharge capacity in the range of the predetermined minimum output number to the maximum output number (for example, No. 24) as the heat exchange heating amount in the main heat exchanger 24. It can be variable. Here, No. 1.0 is the hot water discharge capacity capable of raising the temperature of water at a flow rate of 1 L / min by 25 ° C., and corresponds to the amount of heat generated by the amount of gas consumed by combustion multiplied by the heat exchange efficiency. To do.

The upstream end of the bypass path 6 is branched from the branch position 31 in the middle of the water supply channel 3, and the return path 83 of the immediate hot water circulation circuit 8 is formed at the confluence position 32 on the downstream side (can body 2 side) of the branch position 31. The downstream ends of the are merged. The check valve 30 is interposed in the water supply channel 3 on the upstream side of the merging position 32 and on the downstream side of the branch position 31. Further, in the water supply channel 3 on the downstream side of the confluence position 32, a water entry flow rate sensor 33 for detecting the water flow rate of water entering the can body 2 and a water entry temperature sensor 34 for detecting the water entry temperature are provided. Are each intervened. Reference numeral 35 in FIG. 1 is a drain plug, and the drain plug 35 is provided with a safety valve 36 for preventing overpressure. The safety valve 36 opens when an abnormal water pressure acts in the flow path and exceeds a predetermined upper limit internal pressure (for example, 2 kPa) to release the excess pressure to the outside.

In the hot water supply passage 4, between the outlet of the heat exchanger 21 and the mixing unit 5, the can body temperature for detecting the hot water discharge temperature (can body temperature) of the hot water heated by heat exchange heating in the can body 2 is detected. A sensor 41 and a hot water flow rate adjusting valve 42 are interposed. Further, a hot water supply temperature sensor 43 for detecting the temperature of hot water after the temperature is adjusted by the mixing unit 5 is interposed in the hot water supply passage 4 located on the downstream side of the mixing unit 5. Then, the upstream end of the hot water supply pipe 7 is connected to the connection port 44 at the downstream end of the hot water supply passage 4, and the hot water supply plug 71 is connected to the downstream end of the hot water supply pipe 7. The hot water supply plug 71 can be directly connected to the connection port 44 of the hot water supply passage 4, and in this case, the installation of the hot water supply pipe 7 is omitted. The hot water supply passage 4 and the hot water supply pipe 7 form a "hot water supply passage" for hot water to be discharged from the heat exchanger 21 and to be supplied to the downstream end via the mixing unit 5.

In addition to the hot water supply path 4, the mixing section 5 is connected so that the downstream ends of the bypass path 6 merge. Water separated from the water supply channel 3 can be introduced into the mixing section 5 through the bypass path 6. The mixing portion 5 constitutes a confluence portion between the hot water supply passage 4 and the bypass passage 6. The bypass passage 6 is provided with a bypass flow rate sensor 61 for detecting the bypass flow rate diverging from the water supply passage 3 and a bypass flow rate adjusting valve 62. Then, by controlling the opening degree of the bypass flow rate adjusting valve 62 by the controller 10 described later, a predetermined amount of water from the bypass passage 6 is mixed (mixed) with the hot water from the hot water supply passage 4 in the mixing unit 5. It is possible to supply hot water whose temperature has been adjusted to a predetermined set hot water supply temperature (for example, 43 ° C.) toward the connection port 44 of the hot water supply passage 4.

The immediate hot water circulation circuit 8 has a return path 83 in which the downstream end is connected to the confluence position 32 of the water supply channel 3 from the connection port 82 at the upstream end, and a branch position 84 set in the hot water supply pipe 7 near the vicinity of the hot water tap 71. It is provided with a return flow path 86 including a return pipe 85 having an upstream end branched from the pipe and the downstream end connected to a connection port 82. The circulation pump 81 is interposed in the return path 83, and the check valve 80 is built in the connection port 82. Then, when the circulation pump 81 is operated by the heat retention operation control, the hot water staying in the hot water supply pipe 7 or the like is returned to the water supply passage 3 at the confluence position 32 through the return pipe 85 and the return passage 83. .. Then, the hot water returned to the water supply channel 3 is subsequently sent to the heat exchanger 21 to be heated by the combustion heat of the combustion burner 22, and then returned to the hot water tap 71 side through the hot water supply passage 4 and the hot water supply pipe 7. Will be circulated. In this way, the return pipe 85, the return path 83, the water supply path 3 downstream from the confluence position 32, the flow path in the heat exchanger 21, and the hot water supply path, which are the paths through which hot water is circulated by the operation of the circulation pump 81. The circulation path of the immediate hot water circulation circuit 8 is configured by the route consisting of 4 and the hot water supply pipe 7, and among them, the circulation path is built in the hot water supply device except for the return pipe 85 and the hot water supply pipe 7 installed at the site. 11 is configured.

The operation control of the above hot water supply device is executed by the controller 10. That is, the operation control such as the hot water supply operation control for supplying hot water of the set hot water supply temperature set in the remote controller 101 and the heat retention operation control executed during the hot water supply standby is, for example, the set hot water supply temperature from the remote controller 101 installed in the kitchen. The controller 10 receives the output of the setting signal, the operation signal, and the like of the above, and the output of the detection signal from various temperature sensors and the like, and executes the operation. The controller 10 constitutes a control unit, includes a microcomputer and the like equipped with an MPU and a rewritable memory, and performs the hot water supply operation control and the like based on a program stored in the memory and various data. ..

The remote controller 101 is provided with an immediate hot water switch 102 that allows the user to operate whether to allow or reject the execution of the thermal insulation operation control, and the immediate hot water switch 102 is provided with the thermal insulation operation control. The function of the release switch for releasing is given. If the user turns on the immediate hot water switch 102 in advance, it is possible to execute the heat retaining operation control as described later, and if it is turned off, the heat retaining operation control can be prevented from being performed during the hot water supply standby. Further, if the user switches the immediate hot water switch 102 that has already been turned ON to OFF, the heat retaining operation control is released regardless of whether the heat retaining operation control is executed or not at that time, and the heat retaining operation is stopped until then. The learning about the temperature, which will be described later, is canceled and returned to the initial set value, and the integrated value of the energization time and the like are cleared. As a result, the learning or the like by the heat retention operation control can be canceled and reset by the user's own intention, and the operation of the hot water supply device according to the user's intention can be realized.

In the hot water supply operation control, the water inlet flow rate sensor 33 detects that the hot water supply tap 71 is opened by the user, water enters the water supply channel 3, and the water inlet flow rate becomes equal to or higher than a predetermined minimum operating flow rate. Then, the control is started and the combustion of the combustion burner 22 is started. The required combustion amount (required number) of the combustion burner 22 is the target for the water inlet temperature detected by the water inlet temperature sensor 34, the water inlet flow rate detected by the water inlet flow sensor 33, and the heat exchanger 21 for heating. It is calculated by a set temperature (for example, 65 ° C.), and combustion is controlled at a predetermined combustion amount based on the calculation result. As a result, predetermined high-temperature hot water is supplied to the mixing unit 5 through the hot water supply channel 4. Then, as temperature control control by mixing water in the mixing unit 5, the water inlet temperature detected by the water inlet temperature sensor 34, the can body temperature detected by the can body temperature sensor 41, the water inlet flow rate sensor 33, and the bypass flow rate sensor 61 Based on the flow rate detected by, the mixed water flow rate from the bypass path 6 is calculated so that the hot water after the mixed water reaches the set hot water supply temperature, and the opening degree control of the bypass flow rate adjusting valve 62 is performed based on the calculation result. Will be done. As described above, hot water having a set hot water supply temperature is supplied to the hot water tap 71, and the hot water is discharged from the hot water tap 71.

When the hot water tap 71 is closed by the user, the flow of water in the water supply channel 3 is also stopped, and the detected value of the incoming water flow rate sensor 33 is smaller than the minimum operating flow rate. Therefore, the combustion operation is stopped to control the hot water supply operation. Is finished. Then, the hot water supply tap 71 is in the hot water supply standby state until the hot water supply is re-opened by the user.

Next, the heat retention operation control will be described with reference to FIG. The following heat retention operation control is adapted to immediately stop the heat retention operation and shift to the hot water supply operation control when the hot water supply plug 71 is opened and the hot water supply use is started during the heat retention operation. .. As a premise of the heat retention operation control, when the outlet 103 (see FIG. 1) is plugged into the power supply and the MPU of the controller 10 is started to be energized, the integration of the energization time is started (step S1). Then, after the hot water supply use is started by the ON operation of the operation switch and the opening operation of the hot water supply plug 71, when the hot water supply operation control is completed, the monitoring by the heat retention operation control is started. First, it is determined whether or not the integrated energization time is less than or equal to the set energization time, and after confirming that it is less than or equal to the set energization time (YES in step S2), then the temperature in the detection path reaches the temperature at which the heat retention operation starts or less. It is determined whether or not the temperature has decreased (step S3). If the temperature in the detection path has dropped to the temperature below the start temperature of the heat retention operation, the heat retention operation is started, and at the same time, the integration of the combustion time related to the heat retention operation is started (YES, S4, S5 in step S3).

Here, the in-passage temperature is the temperature of the hot water in the circulation path 11, and as the in-passage temperature, for example, the hot water discharge temperature detected by the hot water discharge temperature sensor 43 can be used. Further, the heat retaining operation start temperature and the heat retaining operation stop temperature described later are temperature values initially set in advance for the heat retaining operation control, and can be determined in relation to the set hot water supply temperature in principle. Since the purpose of the heat retention operation is to enable the hot water of the desired temperature (set hot water supply temperature) to be immediately discharged from the hot water tap 71 when the hot water supply is used next time, it should be determined in relation to the set hot water supply temperature. Because it is rational. For example, when the above-mentioned hot water outlet temperature is used as the in-passage temperature, [set hot water supply temperature −α] ° C. can be set as the heat retention operation start temperature, and [set hot water supply temperature + β] ° C. can be set as the heat retention operation stop temperature. As α, for example, about 5 ° C. can be used, and as β, for example, about 2 to 5 ° C. can be used. In particular, the heat retention operation stop temperature can change the value of β according to the level of the set hot water supply temperature. In this case, the higher the set hot water supply temperature, the larger the β value can be. For example, if the set hot water supply temperature is 43 ° C, β = 2 ° C, and if it is 45 ° C, β = 5 ° C can be set.

As the in-passage temperature to be monitored for the heat retention operation stop temperature, the temperature detected by the hot water discharge temperature sensor 43 can be used, or the temperature sensor arranged at another position of the circulation path 11 can be used. The detected temperature can also be used. For example, the temperature of hot water flowing in the circulation path 11 of the portion returned from the hot water tap 71 side, which is the hot water supply destination (circulation destination), specifically, for example, the water supply temperature detected by the water supply temperature sensor 34 is used as the in-passage temperature. Therefore, it can be compared with the heat retention operation stop temperature. Further, when a switch (for example, a DIP switch) for allowing or prohibiting high-temperature hot water discharge (for example, high-temperature hot water discharge of 60 ° C. or higher) is provided, a preset heat retention operation is started in relation to the above-mentioned set hot water supply temperature. Instead of the temperature, the heat retention operation start temperature can be initially set by another way of thinking.

In the heat retention operation in step S4, the circulation pump 81 is first operated, and then the combustion burner 22 is burned. At this time, as the combustion control for the heat retention operation, continuous combustion is performed in the minimum or small combustion amount range. For example, it is performed by one-stage combustion in which only the capacity switching valve 221 is opened and switched to burn and operate two combustion nozzles, or by two-stage combustion in which the capacity switching valve 222 is also opened and switched to operate three combustion nozzles. be able to.

Then, after confirming that the integrated combustion time, that is, the duration of the heat retention operation is equal to or less than the set combustion time (YES in step S6), it is determined whether or not the temperature in the detection path has risen to the temperature at which the heat retention operation is stopped or more. (Step S7). If the temperature has not risen to the heat retention operation stop temperature, the process returns to step S6 to repeat the determination of the integrated combustion time, and then the determination of the heat retention operation stop temperature in step S7 is repeated. If the temperature in the detection path rises to the temperature at which the heat retention operation is stopped (YES in step S7), the heat retention operation is stopped (step S8). That is, the combustion operation of the combustion burner 22 is stopped, and the circulation pump 81 is stopped. Then, the integrated value of the combustion time is cleared and the process returns to step S1 (step S9).

On the other hand, in the determination in step S6, when the integrated combustion time is not less than or equal to the set combustion time (for example, 1 hour), that is, when the combustion for heat retention operation continues beyond the set combustion time (NO in step S6). , The same temperature value as the current path temperature (the path temperature detected at that time) is newly set as the heat retention operation stop temperature (step S10), and then the heat retention operation stop temperature reset in step S7. The heat retention operation is stopped after the comparison determination with (YES, S8 in step S7). Then, after clearing the integrated value of the combustion time (step S9), the product returns. When the heat retention operation is continued again (steps S4 and S5) and the temperature does not rise to the reset heat retention operation stop temperature even after the set combustion time is exceeded (NO in step S6), the heat retention operation stop temperature is set again. The heat retention operation stop temperature is sequentially changed and set, such as being reset (step S10). That is, the heat retention operation stop temperature can be updated by learning according to changes in pipe heat dissipation based on environmental factors such as the season at that time.

For example, at the turn of the season when the outside air temperature drops sharply, the heat dissipation from the pipes increases, and most of the heat added by the combustion of the combustion burner 22 is lost by the heat dissipation from the pipes. Even if the circulation is continued, it is conceivable that the temperature of the circulating hot water returned by the return path 83 hardly rises. Even in such an environment, it is possible to avoid a situation in which the combustion burner 22 continues to burn continuously for an excessively long time due to the execution of the heat retention operation, while the temperature in the path is early after the heat retention operation is stopped. Since it is considered that the temperature drops to the start temperature of the heat retention operation, the next heat retention operation is started early, and the heat retention function (immediate hot water function) under the environment can be ensured.

By updating by learning the heat retention operation start temperature in this way, the above-mentioned action and effect under the environment at that time can be obtained, but the seasons change sequentially. Alternatively, the installation environment may change, such as when the installation location of the external pipe (for example, the hot water supply pipe 7 or the return pipe 85) is changed. Therefore, in the determination in step S2, when the integrated energization time exceeds the set energization time (NO in step S2), the value of the heat retention operation stop temperature updated by learning is initialized and returned to the initial set temperature value. After that (step S11), the integrated value of the integrated energization time is cleared (step S12), and the process returns. In other words, the passage of time is monitored, and it is assumed that environmental factors (seasonal factors and installation environment) may have changed with the passage of a predetermined period, so the heat retention operation stop temperature updated by learning is returned to the initial set value, and again. Under the current environmental factors, the temperature retention operation stop temperature is determined and updated. As a result, even if seasonal fluctuations or changes in the installation environment occur, it is possible to learn the heat retention operation stop temperature according to the environmental factors, and it becomes possible to execute the heat retention operation control appropriately and effectively. .. As the set energizing time, for example, a time value corresponding to 1 month to 3 months can be set, and a shorter time value (for example, a time value corresponding to 1 month) is used to finely reflect changes in environmental factors. In order to realize the minimum reflection, a longer time value (for example, a time value corresponding to 3 months) can be set as the set energizing time.

<Other embodiments>
The present invention is not limited to the above-described embodiment, but includes various embodiments. That is, the present invention can be applied not only to the water heater of the above embodiment but also to a water heater having another configuration. For example, the present invention can be applied to a hot water storage circulation type hot water supply device as shown in FIG. 3 and a filtration temperature rise circulation type hot water supply device as shown in FIG. In FIG. 3, a plurality of water heaters 12, 12, ... Are connected in parallel, hot water is drawn out from the bottom of the hot water storage tank 14 by the operation of the circulation pump 131, and a predetermined number of water heaters are heating units through the water supply channel. Circulation is possible between the heating unit and the hot water storage tank 14, which is the circulation destination, by entering water into 12, 12, ..., And returning the heated hot water to the top of the hot water storage tank 14 through the hot water supply channel to store hot water. It has a road 13. In addition, the hot water tap 152 is branched in the middle of the circulation path 15 that draws hot water from the top of the hot water storage tank 14 and returns it to the bottom by the operation of the circulation pump 151. Then, during the standby period until the circulation heating control by the circulation passage 13 is suspended and the next circulation heating control is started, the heat retention operation is executed for the circulation passage 13 which is often externally piped. In this case, if the temperature of the hot water in the circulation path 13 drops to the temperature at which the heat retention operation starts, the circulation pump 131 is operated to burn the water heaters 12, 12, ... As a result, the hot water in the hot water storage tank 14 is circulated through the circulation path 13 through the pipes to the water heaters 12, 12, ..., And the temperature of the hot water in the circulation path 13 rises. Then, when the temperature inside the circulation path 13 rises to the temperature at which the heat retaining operation is stopped, the heat retaining operation is stopped. The same learning / updating of the heat retaining operation stop temperature as described in the above embodiment can be applied to such heat retaining operation control.

Further, the one of FIG. 4 is provided with a filtration warming circulation path 16 and a circulation path 17. The filtration warming circulation path 16 is in the middle of the circulation operation in which hot water is taken out from the bathtub H by the operation of the circulation pump 161 and returned to the bottom of the hot water storage tank 18 provided with the filter, while the hot water is introduced into the bathtub H from the top. By injecting a chemical solution for sterilization from the chemical injection tank 162, filtration and sterilization are performed while raising the temperature of the hot water in the bathtub H. Further, the circulation path 17 is heated to a high temperature by a liquid-liquid heat exchanger 171 for heating the hot water in the hot water storage tank 18 and water heaters 12 and 12 which are heating units for the liquid-liquid heat exchanger 171. It is provided with a circulation pump 172 for circulating and supplying the hot water. Then, during standby until the circulation supply of the heat source by the circulation passage 17 is stopped and the next circulation supply is started, the heat retention operation is executed for the circulation passage 17 which is often externally piped. There is. In this case, when the temperature of the hot water in the circulation path 17 drops to the temperature at which the heat retention operation starts, the circulation pump 172 is operated to burn the water heaters 12 and 12. As a result, the hot water from the water heaters 12 and 12 is circulated and supplied to and from the liquid-liquid heat exchanger 171 which is the circulation destination through the circulation path 17, so that the temperature of the hot water in the circulation path 17 rises. .. Then, when the temperature inside the circulation path 17 rises to the temperature at which the heat retaining operation is stopped, the heat retaining operation is stopped. The same learning / updating of the heat retaining operation stop temperature as described in the above embodiment can be applied to such heat retaining operation control.

In the above embodiment, the energization time is integrated by the counter timer (integration unit) in the controller 10, and the learning / updating of the heat retention operation stop temperature is initialized as the set energization time elapses, so that the environmental factor (season) changes. Instead of this, for example, the detection value of the atmosphere temperature sensor (outside air temperature sensor) is used, or the calendar function (date data) by the controller 10 is used to learn the heat retention operation stop temperature. -Updates can be initialized.

3 Water supply channel (circulation channel)
4 Hot water supply channel (circulation channel)
10 Controller (heat retention operation control unit)
12 Water heater (heating part)
13,17 Circulation path 21 Heat exchanger (heating part)
22 Combustion burner (heating part)
34 Water supply temperature sensor (temperature sensor)
43 Hot water temperature sensor (temperature sensor)
71 Hot water tap (hot water supply destination; circulation destination)
81, 131, 172 Circulation pump 83 Return path (circulation path)
102 Immediate hot water switch (release switch)

Claims (3)

Between the heating unit, the circulation path connecting the heating unit and the circulation destination, the circulation pump, and the hot water heated by the heating unit by operating the circulation pump when a predetermined condition is satisfied. A hot water supply device provided with a heat retention operation control unit for executing a heat retention operation that circulates in the circulation to keep the inside of the circulation path warm.
A temperature sensor for detecting the temperature of hot water in the circulation path is provided.
The heat retention operation control unit
When the temperature in the detection path detected by the temperature sensor becomes equal to or lower than the preset heat retention operation start temperature, the heat retention operation is started, while the temperature in the detection path is set in advance by the heat retention operation. If the temperature rises to the above level, the heat retention operation is stopped, and the temperature in the detection path rises to the heat retention operation stop temperature or higher even after a predetermined set time has elapsed since the heat retention operation was started. If not, the temperature inside the detection path of the circulation path at that time is configured to be updated as the heat retention operation stop temperature .
Further, it is provided with an integration unit that integrates the energization time of the heat retention operation control unit.
The heat retention operation control unit is the original in which the heat retention operation stop temperature is initially set each time the energization time integrated by the integration unit reaches a predetermined set energization time set as representing a change in environmental factors. It is configured to return to a value ,
A hot water supply device characterized by this. The hot water supply device according to claim 1 .
A hot water supply device including a release switch for releasing the update content acquired by the heat retention operation control already executed by the heat retention operation control unit. The hot water supply device according to claim 1 or 2 .
The circulation destination includes a hot water supply destination, a water supply channel, a heating unit for heat exchange heating of water supplied through the water supply channel by heat of combustion, and hot water exchanged and heated by the heating unit to the hot water supply destination. It is provided with a hot water supply path for supplying hot water toward the hot water supply and a return path for returning hot water to the water supply channel by branching from the vicinity of the hot water supply destination.
The heat retention operation control unit operates a circulation pump interposed in the return path when waiting for hot water supply, heats the hot water returned through the return path by heat exchange heating in the heating section, and then discharges the hot water to the hot water supply path. A hot water supply device that is configured to.

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