JP7758945B2 - Linked hot water system - Google Patents

Description

The present invention relates to a linked hot water supply system that includes multiple hot water supply devices and a system control device that controls the number of operating hot water supply devices, and that changes the number of operating devices to provide heating capacity according to hot water consumption.

Conventionally, hot water storage systems have been used as hot water supply systems for ordinary households. These systems store hot water heated by a heat pump heat source, which has high operating efficiency, in a hot water storage tank and use this stored water for hot water supply. In order to store hot water in accordance with the user's actual usage, technology is known for determining the optimal operating mode based on usage history, as described in Patent Document 1, for example.

On the other hand, in dormitories, accommodation facilities, sports gyms, and the like, hot water usage can increase rapidly in a short period of time due to concentrated hot water usage caused by multiple users taking showers, etc., and hot water usage can also decrease temporarily before suddenly increasing again. Furthermore, the time of day and number of users using hot water vary greatly from day to day, making it difficult to store hot water appropriately based on usage history, as in Patent Document 1. Therefore, such facilities use linked hot water supply systems that supply hot water by changing the number of operating combustion-type hot water heaters to adjust heating capacity according to hot water usage. Linked hot water supply systems supply hot water at a set target temperature to hot water supply pipes, and hot water users can use hot water at the desired temperature from a hot water tap with a temperature adjustment function.

A linked hot water supply system adjusts the heating capacity of operating water heaters according to hot water usage (the amount of hot water discharged at the target temperature) and changes the number of operating water heaters, making it possible to supply not only large amounts of hot water but also small amounts of hot water with only one operating unit. One example of such a linked hot water supply system is known from Patent Document 2, where the number of operating units is changed based on the amount of hot water used (the amount of water supplied from the water supply pipe and the amount of heat supplied by each water heater).

Japanese Patent Application Laid-Open No. 2008-89208 Japanese Patent Application Laid-Open No. 2007-292383

In conventional linked hot water supply systems, if the heating capacity of the currently operating hot water supply device is insufficient and hot water cannot be supplied at the target temperature, an additional hot water supply device is activated. At this time, the currently operating hot water supply device has often already reached its maximum heating capacity, and the additional hot water supply device takes some time from ignition to increasing its heating capacity and stabilizing the hot water supply, creating issues with its responsiveness to sudden increases in hot water usage.

The linked hot water supply system of Patent Document 2 increases the number of operating units when the hot water supply volume of an operating water heater becomes high, based on the three preset hot water supply volumes of high, medium, and low for each water heater. It also decreases the number of operating units when the hot water supply volume of an operating water heater becomes low. Therefore, in response to a sudden increase in hot water usage, the hot water supply volume of the operating water heater can be increased while the next water heater is driven, improving responsiveness.

On the other hand, each water heater in the linked hot water supply system of Patent Document 2 is controlled so that the amount of hot water supplied is medium for the majority of hot water supply operations, and the number of operating units tends to increase even when the amount of hot water consumption is such that hot water can be supplied without increasing the number of operating units. As a result, the cumulative operating time of each water heater increases and their deterioration progresses more quickly, which may lead to earlier maintenance or replacement times for the linked hot water supply system.

The object of the present invention is to provide a linked hot water supply system that can simultaneously improve responsiveness and suppress the progression of deterioration of the hot water supply device.

The linked hot water supply system of claim 1 comprises a plurality of combustion-type hot water supply devices installed in parallel between a water supply pipe and a hot water supply pipe, and a control means for changing the number of hot water supply devices to be operated depending on hot water consumption. The plurality of hot water supply devices are set to one main hot water supply device that is operated when hot water supply starts, and a sub-hot water supply device for operating additional hot water supply devices other than the main hot water supply device. The control means additionally operates one of the inactive sub-hot water supply devices to supply hot water when the heating capacity of the last of the operating hot water supply devices to be started reaches or exceeds a specified value. The control means learns and memorizes the hot water supply operation status of the plurality of hot water supply devices, sets a high-load time period during which hot water consumption increases, and lowers the specified value for operating additional sub-hot water supply devices during this high-load time period.

With the above configuration, the linked hot water supply system operates the main hot water supply unit to supply hot water when hot water supply starts. When the heating capacity of the last operating hot water supply unit reaches or exceeds a specified value, the number of operating units is increased by one. The control device of this linked hot water supply system sets a time period during which hot water usage increases based on the learned and memorized hot water supply operation status as a high-load time period, and during this high-load time period, the specified value that serves as the judgment criterion for increasing the number of operating units is lowered from the specified value during other high-load time periods. As a result, during high-load time periods, the heating capacity of the last operating hot water supply unit to start operating can be increased while additional sub-hot water supply units can be operated. Therefore, during high-load time periods, the timing of starting operation of the sub-hot water supply unit can be advanced, allowing for a quick response to increases in hot water usage and improving responsiveness. Furthermore, during other high-load time periods, the specified value is higher than during high-load time periods, so an increase in the number of operating units can be suppressed, thereby suppressing the progression of deterioration of the water supply units.

The linked hot water supply system of the present invention according to claim 2 is characterized in that, in the invention according to claim 1, the high load time period is set based on a maximum water flow rate through the plurality of hot water supply devices.
With the above configuration, among the learned and stored hot water supply operation statuses, time periods during which the number of operating units needs to be increased based on the maximum water flow rate are set as high-load time periods. Therefore, the high-load time periods can be set more appropriately based on the hot water supply operation status in which the number of operating units is likely to increase due to the earlier timing of the start of operation of the sub-hot water supply units during the high-load time period.

The linked hot water supply system of the invention of claim 3 is characterized in that, in the invention of claim 1, the high load time period is set based on the rate of increase in the amount of water flowing through the multiple hot water supply devices.
With the above configuration, among the learned and stored hot water supply operation conditions, time periods in which it is preferable to rapidly increase the number of operating units are set as high-load time periods based on the rate of increase in water flow. Therefore, the high-load time periods can be set more appropriately based on the hot water supply operation conditions in which the number of operating units is likely to increase because the timing of the start of operation of the sub-hot water supply units is advanced during the high-load time periods.

The linked hot water supply system of the present invention can improve responsiveness while suppressing the progression of deterioration of the hot water supply device.

1 is a diagram showing a linked hot water supply system according to an embodiment of the present invention; 1 is an explanatory diagram of a hot water supply device constituting a linked hot water supply system according to an embodiment. FIG. 10 is a diagram showing an example of setting a high-load time period based on the learned and stored hot water usage record. 10 is a flowchart of the control of the number of operating units. FIG. 10 is an explanatory diagram of the increase and decrease in heating capacity during normal hours. FIG. 10 is an explanatory diagram of the increase in heating capacity during a high-load time period. FIG. 10 is an explanatory diagram of the transition of a decrease in heating capacity during a high-load time period.

The following describes how to implement the present invention based on examples.

As shown in FIG. 1, tap water is supplied to water supply pipe 1 as indicated by arrow W. A linked hot water supply system 10 is installed so that the tap water introduced from this water supply pipe 1 is heated to a target temperature and supplied to hot water supply pipe 2, which is equipped with multiple hot water taps F1-Fm. This linked hot water supply system 10 includes multiple (here, four) hot water supply devices 11-14 and a system control device 15 as a control device communicatively connected to these hot water supply devices 11-14 to control the number of operating devices. The system control device 15 includes an operation remote control 15a that controls, for example, the outlet hot water temperature of the linked hot water supply system 10. The multiple hot water supply devices 11-14 are connected in parallel between water supply pipe 1 and hot water supply pipe 2, and any of the hot water supply devices 11-14 can supply hot water to the multiple hot water taps F1-Fm. The multiple hot water taps F1-Fm have the function of adjusting the temperature, for example, by mixing the hot water with tap water, so that hot water users can adjust the temperature to their desired level. The number of water heaters that make up the linked hot water supply system 10 is not limited to four, but may be two or more.

Next, hot water heaters 11 to 14 will be described. However, since hot water heaters 11 to 14 have the same configuration, only hot water heater 11 will be described and a description of hot water heaters 12 to 14 will be omitted.
As shown in Figure 2, water heater 11 is a combustion-type water heater configured to heat hot water flowing through heat exchanger 22 by utilizing the heat of combustion of fuel gas in combustion unit 21. Water heater 11 has water supply unit 23 that supplies clean water to heat exchanger 22, and hot water outlet unit 24 that adjusts the temperature of the hot water heated in heat exchanger 22 and outputs the adjusted water.

The combustion section 21 includes a burner 25 with multiple combustion compartments, a fuel adjustment valve 26 that adjusts the flow rate of fuel gas supplied to the burner 25, a combustion fan 27 that supplies combustion air, and an ignition device 28 that ignites the burner 25 using electrical discharge. The burner 25 is equipped with on-off valves 25a to 25d that correspond to the multiple combustion compartments.

The water supply unit 23 has a water supply passage 29 that connects the water supply pipe 1 and the heat exchange unit 22, a water supply valve 30 that opens and closes the water supply passage 29, a water supply temperature sensor 31 that detects the temperature of the clean water (water supply temperature), and a water supply flow rate sensor 32 that detects the flow rate of the clean water (water supply flow rate) supplied to the heat exchange unit 22.

The hot water outlet section 24 includes a hot water outlet passage 34 connecting the heat exchange section 22 and the hot water supply pipe 2, a bypass passage 35 branching off from the water supply passage 29 downstream of the water supply valve 30 and connected to the hot water outlet passage 34, and a bypass flow rate adjustment valve 36. The bypass flow rate adjustment valve 36 adjusts the flow rate of clean water flowing from the water supply passage 29 into the bypass passage 35. The hot water outlet passage 34 is equipped with a first hot water outlet temperature sensor 37 that detects the temperature of the hot water heated in the heat exchange section 22, a second hot water outlet temperature sensor 38 that detects the temperature of the hot water (outlet water temperature) adjusted by mixing the heated hot water with clean water from the bypass passage 35, and a hot water outlet flow rate adjustment valve 39. The hot water outlet flow rate adjustment valve 39 adjusts the flow rate of clean water introduced from the water supply pipe 1 by adjusting the hot water outlet flow rate of the hot water supplied to the hot water supply pipe 2, i.e., is a water flow rate adjustment means that adjusts the water flow rate of the hot water heater 11.

The water heater 11 has a control unit 40 that controls the hot water supply operation of the water heater 11 in cooperation with the system control device 15. The control unit 40 acquires the flow rate detected by the water supply flow sensor 32 and the temperatures detected by the water supply temperature sensor 31 and the first and second hot water outlet temperature sensors 37, 38. Based on these detected flow rates and temperatures, the control unit 40 changes and adjusts the heating capacity by controlling the rotation speed of the combustion fan 27, the opening degree of the fuel adjustment valve 26, and the opening and closing of the on-off valves 25a to 25d, and also adjusts the opening degree of the bypass flow adjustment valve 36. This performs hot water supply operation, supplying hot water at the set target temperature to the hot water supply pipe 2.

For example, if hot water at the target temperature cannot be supplied because the amount of hot water used is large, the control unit 40 adjusts the opening of the hot water outlet flow rate adjustment valve 39 to reduce the amount of water flowing, thereby enabling hot water at the target temperature to be supplied. The amount of water flowing through the hot water supply device 11 is calculated by the control unit 40 based on the flow rate detected by the water supply flow rate sensor 32, the opening of the bypass flow rate adjustment valve 36, and the opening of the hot water outlet flow rate adjustment valve 39.

The system control device 15 sets one of the multiple water heaters 11-14 that are candidates for hot water operation (for example, water heater 11) as the main water heater, and sets the water heaters other than the main water heater (for example, water heaters 12-14) as sub-water heaters. The main water heater is the water heater that is first activated when hot water supply starts. The sub-water heater is a water heater that is not activated when hot water supply starts, but is activated additionally while hot water is being supplied. Since there is one main water heater, the number N of sub-water heaters is N = 3.

When setting up the sub-water heaters, the operation priority (order of additional operation) of the sub-water heaters other than the main water heater, which has the highest operation priority, is set, for example, the first sub-water heater, the second sub-water heater, and the third sub-water heater. Furthermore, to minimize differences in cumulative operation time or operating load between the multiple water heaters 11-14, the system control device 15 sets a rotation that swaps the main water heater and the sub-water heater, for example, periodically or according to cumulative operation time.

The control unit 40 of the main hot water supply unit opens the water supply valve 30 and opens the hot water outlet flow rate adjustment valve 39, for example, fully. The control unit 40 of the sub-hot water supply unit closes the water supply valve 30 and opens the hot water outlet flow rate adjustment valve 39, for example, halfway, less than fully open. When any of the hot water taps F1 to Fm is opened and the water supply flow rate of the main hot water supply unit exceeds a predetermined start flow rate, hot water supply operation begins using only the main hot water supply unit.

When the heating capacity of the main water heater exceeds a specified value, for example, and an additional operation condition is met, and there are inactive sub-water heaters among the operation candidates, the system control device 15 additionally operates one of the inactive sub-water heaters with the highest operation priority. Since the incoming tap water is distributed among multiple operating water heaters, the system control device 15 adjusts the opening of the hot water outlet flow control valve 39 of the water heater that was last to start operating, for example, so that the heating capacity of the water heater that started operating first is maintained.

During hot water supply operation, the system control device 15 learns and stores the hot water supply operation status of multiple hot water supply devices 11-14, for example, as shown in Figure 3. The hot water supply operation status that is learned and stored includes, for example, the number of operating units, water flow rate, heating capacity, and time of day. Then, based on the learned and stored hot water supply operation status, for example, time periods with high hot water usage are set as high-load time periods. In this case, because hot water usage is high, time periods with three or more operating units are set as high-load time periods.

The system control device 15 turns on the high-load time period mode during high-load time periods and turns off the high-load time period mode during normal time periods (time periods other than high-load time periods). Note that, for example, when the linked hot water supply system 10 is in operation for the first time or the learned and stored hot water supply operation status is initialized, the system control device 15 will perform hot water supply operation as a normal time period until at least one day's worth of hot water supply operation status has been learned and stored.

The system control device 15 relaxes the additional operating conditions of the sub-water heater during high-load time periods (when high-load time period mode is ON) compared to the additional operating conditions during normal time periods (when high-load time period mode is OFF). This specified value is set to the normal time period specified value (e.g., maximum heating capacity) during normal time periods, and set to a high-load time period specified value lower than the normal time period specified value (e.g., 50% of maximum heating capacity) during high-load time periods, thereby relaxing the additional operating conditions.

Instead of the number of operating units, a time period with a predetermined standard water flow rate F0 or greater can be set as a high-load time period based on the maximum value of the total water flow rate (maximum water flow rate) of multiple water heaters 11-14. Also, a time period in which the water flow rate increase rate calculated from the total water flow rate of multiple water heaters 11-14 (for example, the maximum increase in total water flow rate within a unit time) is equal to or greater than a predetermined standard increase rate I0 can be set as a high-load time period. Because the number of operating units is likely to increase when high-load time period mode is ON, setting a high-load time period based on the maximum water flow rate or the water flow rate increase rate allows for more appropriate high-load time periods to be set.

For example, when the hot water tap F1 is opened and the water supply flow rate sensor 32 of the main hot water supply device detects a flow rate equal to or greater than the predetermined start flow rate, the main hot water supply device starts operating to provide hot water, and the system control device 15 begins controlling the number of operating units. This control of the number of operating units is explained based on the flowchart in Figure 4. In the figure, Si (i = 1, 2, ...) represents a step.

When control of the number of operating units begins, the number N of sub-water heaters is obtained in S1 and the process proceeds to S2. Then, in S2, since only the main water heater has started operating immediately after hot water supply operation began, the number n of operating sub-water heaters is set to zero and the process proceeds to S3.

In S3, it is determined whether the high-load time period setting is OFF. If the determination in S3 is Yes, the process proceeds to S4, where the normal time period specified value is set as the specified value, and the process proceeds to S6. This sets the specified value to, for example, the maximum heating capacity of the water heater. Note that the normal time period specified value may be lower than the maximum heating capacity.

On the other hand, if the determination in S3 is No, proceed to S5, where the high-load time period specified value is set as the specified value, and proceed to S6. This sets the specified value to be lower than the normal time period specified value, for example, 50% of the maximum heating capacity of the water heater. Note that the high-load time period specified value should be lower than the normal time period specified value and higher than the heating capacity at the start flow rate.

In S6, it is determined whether the heating capacity of the water heater that last started operating has reached or exceeded a specified value. This is the step for determining the additional operating conditions of the sub-water heater. The system control device 15 determines whether the heating capacity of water heaters 11-14 has reached or exceeded a specified value based on various data related to water heater operation that is acquired for learning and storing the water heater operation status. The water heater that last started operating is the main water heater if only the main water heater is operating, and if a sub-water heater is also operating, it is the sub-water heater that last started operating among the operating sub-water heaters.

If the determination in S6 is Yes, proceed to S7. Then, in S7, it is determined whether the number n of operating sub-water heating devices is smaller than the number N of sub-water heating devices. This is the step to determine whether there are any inactive sub-water heating devices that can be additionally operated. If the determination in S7 is Yes, proceed to S8, where one of the inactive sub-water heating devices is additionally operated in S8, and proceed to S9. Then, in S9, the number n of operating sub-water heating devices is incremented by 1, and proceed to S10. At this time, the control unit 40 of the sub-water heating device that received the additional operation command begins operation by opening the water supply valve 30 of that sub-water heating device.

On the other hand, if the determination in S6 is No, the process proceeds to S10 without additionally operating the sub-water heating device. Also, if the determination in S7 is No, there are no inactive sub-water heating devices that can be additionally operated, so the process proceeds to S10 without additionally operating the sub-water heating device.

In S10, it is determined whether the water supply flow rate of the water heater that was last activated among the currently operating water heaters has fallen below the activation flow rate. If the amount of hot water usage decreases, the amount of water flowing through the currently operating water heaters will decrease. To compensate for this decrease, the opening of the hot water outlet flow rate adjustment valve 39 of the water heater that was last activated is preferentially adjusted, reducing the heating capacity. At this time, if the water supply flow rate falls below the activation flow rate, stable hot water operation will become difficult, so this is the step in which the conditions for stopping the water heater that was last activated are determined.

If the determination in S10 is No, the process returns to S3. If the determination in S10 is Yes, the process proceeds to S11, where the operation of the hot water supply device that last started operation is stopped, and the process proceeds to S12. The control unit 40 of the hot water supply device that has been instructed by the system control device 15 to stop operation closes the water supply valve 30 of that hot water supply device to stop operation.

In S12, it is determined whether the number n of operating sub-water heaters is zero. If the determination in S12 is No (n>0), the process proceeds to S13, where the number n of operating sub-water heaters is decremented by 1, and since at least the main water heater is operating, the process returns to S3. On the other hand, if the determination in S12 is Yes (n=0), the operation of the main water heater was stopped in S11, so the process proceeds to S14. Then, in S14, hot water supply operation is terminated and control of the number of operating units is terminated.

Next, an example of the transition of heating capacity during hot water supply operation in normal hours will be described with reference to FIG.
During normal time periods, hot water supply operation begins in state (a) with only the main water heater operating, and then the heating capacity is increased until the main water heater reaches the normal time period specified value U0 (when the additional operation condition is met), and one sub-water heater (first sub-water heater) is additionally operated, transitioning to state (b).Furthermore, upon the satisfaction of the additional operation condition, the second sub-water heater is additionally operated, transitioning to state (c), and then the third sub-water heater is additionally operated, and the heating capacity can be increased to state (d) where all of the multiple water heaters 11 to 14 are operating at maximum heating capacity.

On the other hand, if the hot water supply flow rate decreases from state (d), for example, the heating capacity is preferentially reduced by reducing the opening of the hot water outlet flow rate adjustment valve 39 of the last operating hot water supply device (third sub-hot water supply device). Then, when the water supply flow rate of this third sub-hot water supply device falls below the operation start flow rate (when the operation stop condition is met), operation is stopped. By further reducing the heating capacity and reducing the heating capacity in the reverse order of operation start, the number of operating devices is reduced, transitioning to state (a) via states (c) and (b). When the water supply flow rate of the main hot water supply device falls below the operation start flow rate, hot water supply operation is terminated. Furthermore, even if the amount of hot water usage increases or decreases during hot water supply, the heating capacity of the last operating hot water supply device to start is adjusted, and the number of operating devices is changed according to the additional operation conditions and operation stop conditions.

Next, an example of the increase in heating capacity during hot water supply operation during a high load time period will be described with reference to FIG.
During high-load periods, hot water supply operation begins in state (a) with only the main water heater operating, and then when the heating capacity of the main water heater increases and reaches or exceeds the high-load period specified value H0 (when the additional operation condition is met), one sub-water heater (first sub-water heater) is additionally operated, transitioning to state (b).Furthermore, when the additional operation condition is met, the second sub-water heater is additionally operated, transitioning to state (c), and then the third sub-water heater is additionally operated, and the heating capacity can be increased to state (d) where all of the multiple water heaters 11 to 14 are operating at maximum heating capacity.

In this way, during high-load periods, the next sub-water heater starts operating while the last operating water heater to start operating is increasing its heating capacity. Therefore, during high-load periods, the heating capacity of the linked water heater system 10 increases more quickly than during normal periods, improving responsiveness.

Next, an example of the transition of the decrease in heating capacity during hot water supply operation during a high load time period will be described with reference to FIG.
For example, if the hot water supply flow rate decreases from state (a), the opening of the hot water outlet flow control valve 39 of the last-activated hot water supply device (the third sub-hot water supply device) among the active hot water supply devices is reduced, thereby preferentially reducing the heating capacity and transitioning to state (b). At this time, the reduction is performed so that the water supply flow rate does not fall below the activation flow rate (so that the activation stop condition is not met). If the heating capacity is further reduced, the heating capacity is reduced in the reverse order of activation so that the activation stop condition is not met, maintaining the number of active units, and transitioning to state (c), for example. Maintaining the number of active units allows the heating capacity of the active hot water supply devices to be increased quickly in the event of a sudden increase in hot water usage, resulting in improved responsiveness compared to normal times. This allows for a quick increase in heating capacity, particularly when the majority of multiple hot water users are replaced and hot water usage fluctuates dramatically.

To further reduce the heating capacity from state (c), the last operating water heater (third sub-water heater) to start operation is stopped, and the heating capacity of the other operating water heaters is adjusted to transition to state (d). In this way, the heating capacity of the operating water heaters is adjusted while the number of operating units is reduced one by one in the reverse order of their start-up, thereby reducing the heating capacity of the linked water heater system 10. Although not shown, hot water operation is terminated when the flow rate detected by the water supply flow sensor 32 of the main water heater falls below the start-up flow rate. It is also possible to increase or decrease the heating capacity of the operating water heaters so that they maintain the same heating capacity.

The operation and effects of the linked hot water supply system 10 will now be described.
In the linked hot water supply system 10, the main hot water supply unit operates to supply hot water when hot water supply begins. When the heating capacity of the last operating hot water supply unit reaches or exceeds a specified value, the number of operating units is increased by one. The system control device 15 of this linked hot water supply system 10 sets a time period during which hot water usage increases as a high-load time period based on the learned hot water supply operation status. During this high-load time period, the specified value that serves as the criterion for increasing the number of operating units is lowered from the specified value during other high-load time periods. This allows the sub-hot water supply unit to be operated while increasing the heating capacity of the last operating hot water supply unit. Therefore, the timing of the start of operation of the sub-hot water supply unit can be advanced to quickly respond to increased hot water usage, improving responsiveness. Furthermore, because the specified value is higher during other high-load time periods than during high-load time periods, the increase in the number of operating units can be suppressed, thereby suppressing the progression of deterioration of the hot water supply units.

When high-load time periods are set based on the maximum water flow rate through multiple water heaters, the timing at which the sub-water heater starts operating is advanced when the high-load time period mode is ON, allowing for more appropriate setting of high-load time periods even in hot water operation situations where the number of operating units is likely to increase. Furthermore, when high-load time periods are set based on the rate of increase in the water flow rate through multiple water heaters, the high-load time periods can be more appropriate set even in hot water operation situations where the number of operating units is likely to increase when the high-load time period mode is ON.

The system control device 15 may control the hot water supply operation of multiple hot water supply devices 11-14. Alternatively, an external control device connected to the linked hot water supply system 10 via an internet line may set high-load time periods. Those skilled in the art will be able to implement the above-described embodiments in various modified forms without departing from the spirit of the present invention, and the present invention encompasses such modifications.

1: Water supply pipe 2: Hot water supply pipe 10: Linked hot water supply system 11 to 14: Hot water supply device 15: System control device (control means)
15a: operation remote controller 21: combustion section 22: heat exchange section 23: water supply section 24: hot water outlet section 25: burners 25a to 25d: first to fourth combustion sections 25e to 25h: on-off valve 26: fuel adjustment valve 27: combustion fan 28: ignition device 29: water supply passage 30: water supply valve 31: water supply temperature sensor 32: water supply flow rate sensor 34: hot water outlet passage 35: bypass passage 36: bypass flow rate adjustment valve 37: first hot water outlet temperature sensor 38: second hot water outlet temperature sensor 39: hot water outlet flow rate adjustment valve 40: control sections F1 to Fm: hot water taps

Claims (3)

A linked hot water supply system includes a plurality of combustion-type hot water supply devices installed in parallel between a water supply pipe and a hot water supply pipe, and a control means for changing the number of the hot water supply devices to be operated according to the amount of hot water used.
For the plurality of water heaters, one main water heater is set to be operated when hot water supply starts, and a sub-water heater is set to be operated in addition to the main water heater,
The control means is a linked hot water supply system characterized in that when the heating capacity of the hot water supply device that was last started among the operating hot water supply devices reaches or exceeds a specified value, it operates one of the inactive sub-hot water supply devices to supply hot water, learns and memorizes the hot water supply operation status of the multiple hot water supply devices, sets a high-load time period during which hot water usage increases, and lowers the specified value for operating the additional sub-hot water supply device during this high-load time period. The linked hot water supply system described in claim 1, characterized in that the high-load time period is set based on the maximum water flow rate through the multiple hot water supply devices. The linked hot water supply system of claim 1, characterized in that the high-load time period is set based on the rate of increase in the amount of water flowing through the multiple hot water supply devices.