JP2009192120A - Operation method of hot water storage type hot water supply system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To allow a user to simply select the priority control for preventing an excess over the maximum demand electric power or runout of hot water in real time in an operation method of a hot water storage type hot water supply system having a water heater taking electric power as a heat source. <P>SOLUTION: This operation method of the hot water storage type hot water supply system includes: a step S1 of detecting a margin α<SB>0</SB>of user input; a step S4 of setting a demand time limit; a step S5 of calculating the average electric power; a step S6 of time sharing the demand time limit; a step S9 of estimating the maximum demand electric power in each division time; a step S10 of comparing the margin electric power value αPp with a target demand Pmax; and steps S11, S12 of controlling a heat pump based on the comparison result. Therefore, the user can control the stop and operation time of the heat pump by the input of the margin α<SB>0</SB>and simply select the priority control for preventing an excess over the maximum demand electric power or runout of hot water in real time. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for operating a hot water storage type hot water supply system including a hot water heater using electric power as a heat source in a facility for managing contract power.

  Conventionally, there are various types of power contracts, but it is necessary to receive high-voltage power in facilities that require an electric capacity of approximately 50 kW or more. The contract power in this high voltage power reception is calculated as the largest value among the maximum demand power in each month in the past year including the current month. Here, the maximum demand power is the largest value in a month among all the power used in the facility measured every 30 minutes of the demand time limit. Accordingly, once the maximum value of the used power is updated, the basic charge is continued for at least one year even if the used power value falls below the maximum value. Therefore, to reduce the basic charge, it is necessary to suppress the power consumption so as not to exceed the maximum demand power. For this reason, in a demand control device for a facility including a conventional hot water heater or the like, the power value (demand value) within the demand time period is predicted, and the operation is controlled so that the predicted demand value does not exceed the maximum target demand. It was.

  As such a demand control device, based on the predicted value of power used for loads other than the heat storage load such as an electric water heater, the preset target power, and the required power consumption of the heat storage load, the operation of the heat storage load In order to prevent the total power used from exceeding the target power, a heat storage load is controlled based on the control content scheduled within a predetermined time zone (see, for example, Patent Document 1).

  However, in the technique as disclosed in Patent Document 1, since the heat storage load can be controlled only within a time period scheduled in advance based on the required power consumption, power control using the heat storage load cannot be performed in real time. In addition, according to the user's request, setting of operation control to change the maximum demand power excess and hot water priority control, such as priority control to prevent excess of the maximum demand power and priority control to prevent hot water out of the water heater Couldn't be done easily. For this reason, for example, when the user wants to reduce the electricity bill instead of when the hot water may occur, or when he wants to avoid causing the hot water to run even in a short time, the user performs necessary operation control flexibly. It was difficult.

Japanese Patent Laid-Open No. 9-9502

  The present invention has been made to solve the above problem, and in the management of contract power of a facility that includes a water heater that uses power as a heat source as an electric power load, the maximum demand power is exceeded in accordance with the state of use of the facility. It is an object of the present invention to provide an operation method of a hot water storage type hot water supply system in which a user can easily select priority control for prevention of hot water supply or prevention of hot water supply in real time.

  In order to achieve the above object, the invention according to claim 1 is the contract form in which the contract power in each month for one year from the start of electricity use is the largest value among the maximum demand power from the start of electricity use to that month. In the operation method of the hot water storage hot water supply system having a hot water supply system that uses the electric power used in the facility of the facility as a heat source, the step of predicting the average power per predetermined time of the entire contract unit, the predicted average power value, Obtaining a calculated value obtained by multiplying the maximum demand power by a predetermined margin rate, and controlling the operation of the electric power of the water heater so that the calculated value does not exceed the maximum demand power. The rate value can be arbitrarily set according to the user's request.

  According to the first aspect of the present invention, since the margin rate value can be arbitrarily set according to the user's request, the user can update the margin rate setting according to the facility usage status, and set the margin rate value to a large value. Easy selection in real time, such as priority control for preventing overrunning of maximum demand power by strengthening power suppression of hot water heaters, and preventing hot water shortage by weakening power control of water heaters by setting a small margin rate Can improve convenience.

  An operation method of the hot water storage type hot water supply system according to the first embodiment of the present invention will be described with reference to the drawings. The operation method of the hot water storage type hot water supply system of the present embodiment uses the largest value from the month when electricity is first used to the current month among the maximum demand power for each month in the average power for each time period determined as the contract unit time. In facilities that have a contract form of contract power for each month for one year from the start, the average power (referred to as demand) for each predetermined time (referred to as demand time limit) of the entire contract unit including the water heater is predicted and predicted. In addition, the water heater is regularly operated and controlled (referred to as demand control) so that the average power (referred to as the predicted demand value) does not contribute to the renewal of the maximum demand power by exceeding the maximum demand power of the contract facility. , The power of the water heater is controlled based on a calculated value obtained by multiplying a predetermined margin rate, and the margin rate value can be arbitrarily set according to the user's request.

  FIG. 1 shows a configuration of a hot water storage type hot water supply system applied to the present embodiment. This hot water storage type hot water supply system includes a water heater 1 serving as an electric power load and a power source 2 for supplying electric power to the water heater 1. The water heater 1 includes a hot water storage tank 4 for storing hot water, a heat pump unit (HPU) 5 having a plurality of heat pumps for warming and supplying hot water to the hot water storage tank 4, and an electronic control unit for controlling the hot water storage tank 4 and the HPU 5 and the like. (Electronic control unit: referred to as ECU) 6 and a communication unit 7 that communicates the power value measured by the power measurement unit 3 separately provided in the facility to the ECU 6 by wire or wirelessly. The power measuring unit 3 measures the power of the entire contract unit in the facility including the power consumption of the power source 2.

  The ECU 6 detects a CPU 8 that controls the entire hot water supply system, an operation control unit 9 that controls the operation of the HPU 5, an α setting unit 10 that sets a predetermined margin rate α for the maximum demand power, and a hot water tank 4 that runs out of water. Hot water outage detection unit 11, timer unit 12 having a plurality of timers (I, II, III, IV) such as power measurement time, remote controller 13 for remote control of ECU 6, and power consumption state and hot water out state for the user And a warning generation unit 14 that issues a warning or the like accordingly. The α setting unit 10 is configured so that the user can arbitrarily set the α value of the margin ratio. For example, the α value can be set by manually inputting the α value on a liquid crystal display equipped with a touch panel, This can be done by displaying a predetermined α value on the liquid crystal display in advance and selecting the desired α value, or inputting or selecting the α value using the remote controller 13. The warning generation unit 14 generates various warnings. For example, when the power value measured by the power measurement unit 3 approaches the maximum demand power value, or when the hot water storage tank 11 is detected by the hot water detection unit 11 On the basis of the hot water running condition of 4, the user is warned with a blinking lamp display or voice.

  Further, the hot water storage tank 4 and the HPU 5 are pipes 20 (double wires) for passing water having a low temperature and pipelines 21, 22, 23, 24 (black thick lines) for passing hot water as pipelines for supplying water and hot water. ). This pipe 20 has a bypass valve 25 that bypasses the flow of water and a water stop valve 26 that stops supply water, and the pipe 21 has a relief valve 27 that partially discharges hot water and a temperature control valve 28 for temperature adjustment. The pipe 22 includes a pressure reducing valve 29 and a water stop valve 26 for reducing the water pressure (or hot water pressure). The pipes 23 and 24 supply hot water (up to 90 ° C.) from the hot water storage tank 4 and set hot water whose temperature is adjusted by the temperature control valve 28 to the hot water tap 30 and the mixing tap 31 provided at the end of each pipe. Then, hot water and temperature-controlled hot water are respectively output from each plug. A hot water outlet side and a water inlet side of the hot water storage tank 4 are respectively provided with a temperature sensor 32 for measuring the temperature of the hot water and a flow rate counter 33 for measuring the amount of water. The temperature sensor 32 is connected to the hot water detection unit 11, and the hot water detection unit 11 detects the hot water using the temperature sensor 32 at the upper part of the hot water storage tank 4. Here, the hot water out means that the temperature of the hot water in the hot water storage tank 4 is lowered and the hot water is in a water state.

  In the operation of the hot water storage type hot water supply system having the above-described configuration, the user sets a margin rate α for the maximum demand power in advance, and after setting the margin rate α, the hot water heater 1 is operated and controlled in the following three stages. In the first stage, first, the average power is calculated at regular time intervals Ts (minutes) immediately after the demand time limit (generally 30 minutes) is updated, and the second stage is the demand time of the average power calculation. The power value of the water heater 1 that can be consumed within the time limit is calculated, and in the third stage, the predicted demand value Pp at that time is the maximum demand power of the contract power (the maximum power value in the past year (30-minute average)) That is, when the target demand Pmax exceeds a value obtained by multiplying the margin rate α, the operation is stopped for the time interval Ts (minutes).

  For this reason, the power measuring unit 3 measures the power consumption of the entire contract unit of the facility including the HPU 5 serving as the power load of the water heater 1 and other power loads of the facility. The measured power value is transmitted from the communication unit 7 to the CPU 8 of the ECU 6. The CPU 8 sets the time unit for obtaining the average power from the power value as the demand time period T1 (30 minutes) of the contract unit time, and calculates the average power (demand) for each demand time period T1. Further, the CPU 8 obtains the average power Pave from the update to the present time at every predetermined time interval Ts obtained by further dividing the demand time period T1 (here, T1 is divided into 6 for 5 minutes). This divided time interval Ts is a time interval for determining whether the HPU 5 is operating or stopped. Further, in the HPU 5 that requires time for preheating the refrigerant, the time interval Ts is selected to be 5 minutes in consideration of the case where several minutes are required from the start of normal operation to the start of hot water.

  Further, the CPU 8 controls the timer I that measures the elapsed time t1 since the power value update and the timer II that measures the time interval Ts in the timer unit 12, and the maximum demand predicted power of the facility within the demand time limit T1 (30 minutes). (Pp) (predicted demand value) is predicted every Ts time. Therefore, first, at the time of calculating the average power Pave, the power value of the water heater 1 that can be consumed in the remaining time within the demand time limit is calculated. The power consumption of the water heater 1 is substantially determined by the power consumed by the HPU 5 that uses a large amount of power. The demand predicted power for the remaining time (30-t1) from the current time t1 of the demand time period T1 of the power used by the HPU 5 is obtained as Ph (30-t1) / 30. Here, Ph is determined by the power consumption per demand time period of all heat pumps used in the HPU 5, and is the maximum predicted power consumption per demand time period (30 minutes) of the HPU 5.

Next, the predicted demand value Pp in the demand time period of the entire contract unit of the facility is obtained. The predicted demand value Pp is obtained by adding the demand predicted power Ph (30-t1) / 30 consumed in the remaining time of the demand time limit of the HPU 5 to the average power Pave at the current time t1 after the demand time period update. As a result, the predicted demand value Pp becomes as follows.
(Equation 1)
Pp = Pave + Ph (30−t1) / 30 (1)

  Thus, the predicted demand value Pp can be easily obtained from the average power Pave and the demand predicted power Ph (30-t1) / 30 of the HPU 5. Further, the CPU 8 compares the predicted demand value Pp, which is the contract power, with αPmax which is a value obtained by multiplying the maximum demand power (30-minute average value) Pmax [kW] (referred to as target demand) in the past year by α. The operation control unit 9 is controlled so that the value Pp does not exceed αPmax, and the operation control unit 9 switches the HPU 5 on and off to control the operation of the water heater 1.

  As described above, the operation method of the hot water storage type hot water supply system of the present embodiment predicts the maximum demand power for each demand time period (30 minutes), and the hot water heater 1 so that the predicted value does not exceed α times the target demand Pmax. The operation of the HPU 5 that is the power load of the vehicle is controlled. That is, the power of the water heater is operated based on a calculated value obtained by multiplying the predicted average power value for each predetermined time in the contract unit by the predetermined margin rate α with respect to the maximum demand power (target demand) as the contract power. It is something to control. Hereinafter, the operation method of this hot water storage type hot water supply system will be described with reference to the flowchart of FIG.

In FIG. 2, first, when the user inputs a predetermined margin rate α ₀ in the α setting unit 10, the CPU 8 detects the input margin rate α ₀ (S1), and the currently set margin rate α is determined. If it is α ₀ (YES at S2), the setting of the margin rate α is not changed, and if the currently set margin rate α is not α ₀ (NO at S2), the value of the margin rate α is set to α. Update to ₀ (S3). After the demand time period update, the elapsed time t1 of the timer I of the timer unit 12 is set to zero (S4), the average power Pave calculated from the power value of the power measuring unit 3 is set to zero (S5), and the timer unit 12 Time t2 for obtaining the average power Pave in the timer II is set to zero (S6). Next, the CPU 8 calculates the average power Pave based on the power value of the power measuring unit 3 (S7), and when the time t2 is less than Ts (NO in S8), the CPU 8 returns to Step 7 and returns to the average power Pave in the Ts period. If the time t2 is larger than Ts (YES in S8), the average power Pave calculated in step 7 and the average power demand prediction within the remaining demand time period (30-t1) of the HPU 5 are calculated. The predicted demand value Pp is obtained from the sum of the electric power Ph (30−t1) / 30 (S9), and the calculated value Pp × α obtained by multiplying the predicted demand value Pp by the margin rate α is used as the margin power value. αPp is obtained by calculation, and the obtained margin power value αPp is compared with Pmax of the target demand (S10). As a result of the comparison, if the marginal power value αPp is larger than Pmax of the target demand (determination formula Pp × α> Pmax) (YES in S10), the CPU 8 issues a stop command for the HPU 5 (S11), and NO in step 10 In the case, the stop command for the HPU 5 is canceled (S12).

  If the time t1 is less than the demand time limit of 30 minutes (NO in S13), the process returns to step 6, resets t2 to zero, and repeats steps 6 to 11 again. If YES in step 13 (when the demand time period of 30 minutes has elapsed), the process returns to step S2, resets t1 to zero, and proceeds to measurement in the next demand time period.

  At this time, the determination formula Pp × α> Pmax is replaced with Pp> (Pmax / α). Therefore, when α> 1, the target demand Pmax is apparently smaller than the predicted demand value Pp. It is set. Therefore, the HPU 5 can be stopped early with a margin before the predicted demand value Pp exceeds the target demand Pmax. Thereby, it is possible to control so that the predicted demand value Pp does not exceed the target demand Pmax as α is increased to 1 or more. On the other hand, when α <1, since Pp <(Pmax / α), the target demand Pmax is apparently set larger than the predicted demand value Pp. Accordingly, the predicted demand value Pp is likely to exceed the target demand Pmax, and therefore, the release of the stop command for the HPU 5 is accelerated, so that the stop of the HPU 5 is reduced and it is easy to prevent hot water shortage.

  FIG. 3 shows the relationship between the change in the predicted demand value Pp and the control command for each time interval Ts (5 minutes) in the demand time limit of 30 minutes, taking as an example the case of α> 1 in demand control based on the above flowchart. In addition, Phmax shows the demand prediction electric power Ph (30-t1) / 30 of the said Formula 1. In FIG. 3, the water heater 1 is controlled to stop the HPU 5 when it is predicted that Pp on the vertical axis exceeds Pmax / α lower than Pmax. Therefore, if the predicted demand value Pp between 5 minutes and 10 minutes is predicted to exceed Pmax / α at the elapsed time t1 = 5 minutes, the CPU 8 issues a stop command for the HPU 5 at that time. In addition, if it is predicted that Pp exceeds Pmax / α in each of 5 minutes from 10 minutes to 20 minutes, HPU 5 is stopped even if t1 is between 10 minutes and 20 minutes. On the other hand, if it is predicted that Pp will be Pmax / α or less during 20 minutes to 25 minutes at t1 = 20 minutes, the CPU 8 issues an operation command at that time. Furthermore, if it is predicted that Pp will be equal to or less than Pmax / α for 5 minutes (Ts) of 20 to 30 minutes, the operation is continued.

  Thus, when α> 1 and the marginal power value αPp is provided, the target demand is the same as when the target demand is set to a low value of Pmax / α, and the stop command for the HPU 5 is issued early and the stop time is lengthened. Since the HPU 5 can be controlled as described above, demand control can be performed so as not to exceed the target demand Pmax, and an increase in the electricity usage fee can be suppressed.

  On the other hand, the case of α <1 (not shown) can be considered in the same manner. In this case, the predicted average power Pp may exceed the target demand Pmax due to Pp <(Pmax / α). The stop time of the HPU 5 can be shortened, the operation time can be lengthened, and the hot water run-out time can be reduced.

  Here, when the value of the margin rate α is changed, the demand control will be described with reference to FIG. FIG. 4 measures the power data and hot water amount data in the restaurant P shown in Table 1 below, and based on the results, the maximum power (kW) and hot water run-out time (h ) Shows the simulation results. The horizontal axis of the graph of the figure shows the value of the margin rate α, and the left and right vertical axes show the hot water run-out time (h) and the maximum power (kW), respectively. The hot water run-out time (h) indicates the total hot water run-out time occurring in 13 days.

  Table 1 shows each specification example such as the number of heat pumps in the store P, the power consumption of the heat pump (per demand time limit), the maximum hot water storage amount of the hot water storage tank, the power factor of the load equipment, and the basic power unit price of the contract power. . In this simulation, the number of heat pumps was calculated by setting an appropriate number for the store P by pre-calculation (here, three), and the initial value of the target demand Pmax of the maximum demand power was calculated as zero. In addition, it is calculated by basic charge = charge unit price × contract power × <185−power factor> / 100.

  As shown in FIG. 4, when α = 0.90 to 1.02, the hot water run-out time is 0, and the maximum power changes from about 81 kW to 78.3 kW. In addition, at α = 1.02 to 1.10, the hot water run-out time increases from 0 to about 21 hours, and the maximum power changes from about 77.8 kW to 77.2 kW. Furthermore, at α = 1.10 to 1.20, the hot water run time increases from about 21 to 62 hours, and the maximum power is controlled to a constant value of about 77.2 kW, so that α is 1.10. Exceeding the maximum demand power Pmax (contract power) can be suppressed to 77 kW. When α is 1.02 or more, the hot water run-out time is abruptly increased, and when α is 1.02 or less, the increase in maximum power is increased. That is, as the value of α increases, the maximum power decreases and the hot water run-out time increases, so that the maximum power and hot water run-out time can be changed by changing the margin rate α.

  Here, for example, when the maximum demand power of the contract power is 78 kW, and the margin rate α is set to 1.02, the hot water run-out time becomes 0 and the maximum demand power becomes about 77.8 kW. It is possible to control to below the electric power, and it is possible to suppress the excess of the electricity charge. Here, α = 1.02 is an initial standard set value when the maximum demand power is 78 kW. In order to more reliably suppress the hot water run-off time even when the maximum demand power is exceeded with respect to this standard setting, the α value is set to α = 0.98 (or 0.98 or less), for example. For example, the maximum power increases to 79 kW, but the stop time of the HPU 5 is reduced as compared to when α = 1.02. As a result, even if the α value at which the hot water run-out time first becomes 0 in the simulation is slightly shifted to the lower side by about 0.04, the hot water run-out can be surely prevented. On the other hand, if it is desired to more reliably suppress the excess of the maximum demand power even if the hot water run-out time becomes longer, for example, α may be set to 1.06 (or 1.06 or more).

  Therefore, depending on the usage of the facility's power and hot water storage system, the user wants to prevent the maximum demand power from being exceeded, or to prevent the water heater from running out of hot water. When the demand power update and the tolerance of hot water change, change the setting of the margin rate α to allow the setting of the maximum power that can be allowed to exceed the maximum demand power and the hot water supply to run out It is possible to change the setting of the time for running out of hot water according to the priority of the user. Here, an example of a selection menu in which the user sets the α value in the α setting unit 10 is shown in Table 2 below.

  The selection menu and the margin rate α in Table 2 can be displayed on a display panel or the like used in the α setting unit 10. The selection menu settings A to E shown in Table 2 correspond to a margin ratio α of 0.98 to 1.06, and the selection menu setting “OFF” indicates, for example, that the user runs out of hot water when the store is operating. This is for stopping the power peak cut function for suppressing the maximum demand power and setting the HPU 5 for continuous operation when it is absolutely not allowed. In this selection menu, as the arrow X goes from setting B to setting A and “OFF”, the hot water prevention function works more strongly, and as shown by arrow Y, the setting B goes from setting B to setting E. This shows that the power peak cut function works strongly.

  In Table 2, the standard setting value is α = 1.02. This is based on the data obtained in advance by the simulation shown in FIG. This is initially set as the α value in a state where it does not exceed. Therefore, this standard set value is not always fixed in the simulation because the calculation results differ depending on the configuration of the hot water system such as heat pumps and hot water tanks used in stores and facilities and the performance specifications of the equipment. It depends on the equipment used. For example, it is possible to set the selection menu so that the standard set value is α = 1 and priority is given to the power peak cut as α becomes larger than 1. At this time, α is set to 1 in the case of hot water prevention priority. In addition to reducing to the following, the setting may be immediately set to “OFF”.

  Further, the value of α can be set continuously even if it is not multistage. Therefore, since the α value can be arbitrarily set according to the user's request, the user can freely control the operation according to the priority order of the necessary setting. Further, this α value is used even when the hot water supply system is in operation, for example, when a warning such as running out of hot water or exceeding the maximum power is issued by the warning generating unit 14, or when the hot water supply system runs out of business. If you want to prevent it, or if you want to prevent the maximum demand electricity from being exceeded, you can change the setting in real time.

  As described above, according to the operation method of the hot water storage hot water supply system of the present embodiment, the margin rate α can be arbitrarily set according to the user's request, so that the user can set the margin rate α according to the facility usage situation. Can be updated. Accordingly, by setting the margin rate value to be greater than 1, priority control for excess power prevention that prioritizes the prevention of excess of the maximum demand power by strengthening the power suppression of the water heater and setting the margin rate α to be less than 1 This makes it easy to select in real time whether the user needs to exceed the maximum power demand and change the hot water out time, such as priority control for hot water prevention that prioritizes hot water prevention by weakening the power suppression of the water heater. , Convenience increases.

  Moreover, in the hot water storage type hot water supply system of this embodiment, since the hot water storage capacity of the hot water storage tank 4 of the water heater 1 is large (in this case, 370 L), the temperature of the hot water suddenly decreases even if stopped instantaneously. Without affecting the operation of the hot water supply function. In addition, since power control can be performed without stopping other power loads (for example, lighting devices) in the operating state, it is possible to prevent functional degradation of facilities having many power loads in facilities accompanying power control. Therefore, since it becomes difficult for the entire facility to be affected by the power control, it is possible to suppress the deterioration of the function of the facility during the power control, and to prevent the maximum demand power from being updated or to prevent the hot water from running out.

  Further, in the heat pump type water heater of the present embodiment, since it takes time to reheat the refrigerant, it often takes several minutes from the start of normal operation to the start of hot water, and in high frequency on-off, There is a possibility that a loss of consuming only energy without leading to hot water may occur, but in the power control of this embodiment, the operation stop time interval is set to 5 minutes, so that the energy efficiency of the HPU 5 can be increased and used. It is possible to reduce power consumption in power control.

  Further, the power measurement unit 3 can be controlled by the CPU 8 by making the communication unit 7 bidirectional communication. Moreover, the electric power measurement part 3 which measures the electric power of the whole plant | facility may be in the hot water storage type hot-water supply system 1 itself, and may exist outside.

  In addition, this invention is not restricted to the said embodiment etc., Furthermore, it can change suitably. For example, in the simulation of the maximum power and the hot water run time of the present embodiment, an example in which α is calculated from 0.90 to 1.20 is shown, but the value of α is not limited to this. In addition, specification data such as heat pumps and hot water storage tanks necessary for simulation, contract power values, and the like may be input from the selection menu screen.

The block diagram of the hot water supply system in the operating method of the hot water storage type hot water supply system which concerns on embodiment of this invention. The flowchart figure of the said operating method. The figure explaining the relationship between the change of the predicted demand power within the demand time limit based on the said operation method, and a control command. The graph which shows the relationship between the margin rate in a store based on the said driving | operation method, the maximum demand electric power, and hot water run-out time.

Explanation of symbols

1 Water Heater 4 Hot Water Storage Tank 5 Heat Pump Unit α Margin

Claims (1)

A hot water heater that uses the power used in the facility of the contract form in which the contract power for each month for the year from the start of electricity use is the largest of the maximum demand power from the start of electricity use to that month. In the operation method of the hot water storage type hot water supply system having,
Predicting the average power for a given time for the entire contract unit;
Obtaining a calculated value obtained by multiplying the predicted average power value by a predetermined margin for the maximum demand power;
A step of operating and controlling the power of the water heater so that the calculated value does not exceed the maximum demand power,
A method for operating a hot water storage type hot water supply system, wherein the value of the margin rate can be arbitrarily set according to a user's request.

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