JP7125001B2 - Hot water storage water heater - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot water storage apparatus, and more particularly to a technique for effectively utilizing residual hot water remaining in a hot water storage tank due to prediction errors when storing hot water consumption predicted by learning control.

Conventionally, a heat pump heat source device in which a compressor, a condensation heat exchanger, an expansion means, and an evaporative heat exchanger are connected by a refrigerant circuit, a hot water storage tank for storing hot water heated by the heat pump heat source device, A hot water storage and hot water supply apparatus equipped with a circulation pump for circulating hot water between the hot water storage tank and the heat pump heat source, and an auxiliary heat source for reheating the hot water in the hot water storage tank when the temperature of the hot water drops is widely put into practical use. It is

In this type of hot water storage and hot water supply apparatus, the hot water usage is learned and stored to predict the future hot water usage, and before the hot water is used, the heat pump heat source is driven to generate the heat amount corresponding to the predicted hot water usage. Storing hot water in a hot water storage tank is also widely practiced.

Here, if the actual amount of hot water supply is less than the estimated amount of hot water supply, residual hot water may remain in the hot water storage tank after the hot water supply for the day is finished. In this case, it is desirable to carry out the hot water storage operation in consideration of the residual hot water. However, since the temperature of the residual hot water drops due to heat dissipation, it is not always possible to maintain the temperature above the reheating required temperature when supplying hot water the next day. Depending on the temperature, the temperature during hot water storage operation on the next day differs. Therefore, it is a difficult problem how to add the above-mentioned residual hot water in the hot water storage operation for the next day.

In the hot water storage type hot water supply system of Patent Document 1, when the hot water storage tank has a high temperature layer, an intermediate temperature layer above the reheating effective temperature, and a low temperature layer, the high temperature layer and the intermediate temperature layer are mixed. , to lower the temperature of the upper part in the hot water storage tank and improve the durability against running out of hot water for reheating.

Japanese Patent No. 5454534

As described above, when residual hot water remains in the hot water storage tank, the temperature of the residual hot water drops due to heat radiation by the next morning, and becomes intermediate hot water at a temperature lower than the hot water supply set temperature. When the medium-temperature water is heated by the heat pump heat source equipment, there is a problem that the COP of the heat pump heat source equipment is lowered.

SUMMARY OF THE INVENTION An object of the present invention is to provide a hot water storage and hot water supply apparatus capable of improving the COP of a heat pump heat source machine when performing a hot water storage operation in consideration of residual hot water.

A hot water storage and hot water supply apparatus according to claim 1 comprises a heat pump heat source device comprising a compressor, a condensing heat exchanger, an expansion means, and an evaporative heat exchanger connected by a refrigerant circuit, and a hot water heated by the heat pump heat source device is stored. a hot water storage tank, a circulating heating passage including a circulation pump that circulates hot water between the hot water storage tank and the heat pump heat source device, and a hot water storage tank for reheating and discharging hot water when the temperature of hot water in the hot water storage tank drops A hot water storage and hot water supply apparatus including an auxiliary heat source, predicting the future hot water consumption by learning and storing the hot water supply usage condition, and driving the heat pump heat source before using the hot water supply to achieve the predicted hot water consumption. In a hot water storage hot water supply device that stores an equivalent amount of heat in a hot water storage tank,
A residual temperature estimating means is provided for estimating a temperature in the case where the temperature of the residual hot water in the hot water storage tank decreases due to heat radiation until the next hot water storage operation, and the residual hot water temperature estimated by the residual temperature estimating means is used for the next hot water storage operation. When the temperature reaches a temperature that requires reheating by the auxiliary heat source unit during operation, a homogenization process is performed to homogenize the hot water temperature in the hot water storage tank, and when the outside air temperature is below the set temperature, As a freeze prevention operation for preventing freezing of the circulation heating passage, the circulation pump is driven to circulate hot water. Circulation is performed by the circulation heating passage with a passage configuration that includes the hot water storage tank, and the anti-freezing operation in a state where the homogenization process is not performed is characterized by performing circulation by the circulation heating passage with a passage configuration that bypasses the hot water storage tank. and

According to the above configuration, the residual temperature estimating means for estimating the temperature of the hot water remaining in the hot water storage tank during the next hot water storing operation is provided, and the residual hot water temperature estimated by the residual temperature estimating means is used as the auxiliary heat source during the next hot water storing operation. When the temperature reaches a level that requires reheating by the machine, a uniform process is performed to equalize the temperature of the hot water in the hot water storage tank. It is possible to prevent the COP of the heat pump heat source from decreasing during the next hot water storage operation.
In the anti-freezing operation for the homogenization process, since circulation is performed by a circulation heating passage with a hot water storage tank, there is no need to operate the heat pump heat source for anti-freezing, which saves energy. Further, in the anti-freezing operation when the homogenization process is not performed, circulation is performed by the circulating heating passage with a passage configuration bypassing the hot water storage tank, so that the temperature stratification in the hot water storage tank can be maintained.

The hot water storage and hot water supply apparatus according to claim 2 is characterized in that, in the invention according to claim 1, the homogenization process is performed by driving the circulation pump to agitate the inside of the hot water storage tank while not driving the heat pump heat source device. there is
According to the above configuration, the inside of the hot water storage tank can be agitated using the circulation pump.

In the hot water storage apparatus of claim 3, in the invention of claim 1 or 2, when the residual hot water is not heated by the heat pump heat source device during the next hot water storage operation, the residual hot water temperature estimated by the residual temperature estimating means is The homogenization process is not performed even if the temperature is such that reheating by the auxiliary heat source is required during the next hot water storage operation.

According to the above configuration, for example, when the amount of residual hot water is small, the residual hot water is not heated by the heat pump heat source equipment during the next hot water storage operation, so that the residual hot water temperature is not reheated by the auxiliary heat source equipment during the next hot water storage operation. Even at the required temperature, it is advantageous not to carry out the homogenization treatment.

According to a fourth aspect of the present invention, there is provided a hot water storage and hot water supply apparatus according to any one of the first to third aspects of the invention, wherein the homogenization process is performed immediately before the next hot water storage operation is started.
According to the above configuration, by performing the homogenization process immediately before starting the next hot water storage operation, it is possible to maintain the homogenization state in the hot water storage tank during hot water storage.

As described above, the present invention has various effects.

1 is an overall configuration diagram of a hot water storage and hot water supply apparatus according to an embodiment of the present invention; 4 is a flow chart of hot water supply usage amount data acquisition control. 4 is a flowchart of hot water storage operation control; 4 is a flow chart of equalization processing when residual hot water is generated in the hot water storage tank. 4 is a time chart of predicted hot water supply consumption and hot water storage operation hot water quantity; 4 is a time chart showing a standby time until the next hot water storage operation when residual hot water is generated in the hot water storage tank.

EMBODIMENT OF THE INVENTION Hereinafter, the form for implementing this invention is demonstrated based on an Example.

First, based on FIG. 1, the overall configuration of the heat pump water heater 1 will be described.
The heat pump water heater 1 has a hot water storage unit 2 and a heat pump heat source device 3. The hot water storage unit 2 includes a hot water storage tank 4, a gas combustion type auxiliary heat source device 5, and other devices (pipes, valves, temperature sensors, etc.). etc.) and an exterior case 2 a that covers the hot water storage and hot water supply unit 2 . The hot water supply unit 2 stores hot water heated by driving the heat pump heat source 3 in the hot water storage tank 4 and uses the stored hot water for hot water supply and filling of the bathtub 6 with hot water. In addition, hot water taken out from the hot water storage tank 4 can be heated by the auxiliary heat source device 5 as needed and used for hot water supply, bath reheating, and the like.

A hot water discharge passage 7 for discharging hot water stored in the hot water storage tank 4 is connected to the upper portion of the hot water storage tank 4 . A water supply passage 8 for supplying tap water from a tap water source to the hot water storage tank 4 is connected to the lower portion of the hot water storage tank 4 . A bypass passage 9 branched from the water supply passage 8 is connected to the hot water discharge passage 7, and a hot water mixing valve 10 capable of adjusting the mixing ratio of mixing the hot water of the hot water discharge passage 7 and the clean water of the bypass passage 9 is interposed at this connection portion. It is A hot water supply passage 11 is connected to the hot water mixing valve 10, and the hot water mixed by the hot water mixing valve 10 flows through the hot water supply passage 11 and can be supplied to a hot water tap or the like (not shown). Hot water can be filled in the bathtub 6 through a hot water filling passage 13 connected to the reheating passage 12.例文帳に追加The hot water filling passage 13 is provided with an on-off valve 13a for hot water filling.

A forward hot water passage 16 for supplying hot water to the heat pump heat source device 3 is connected to the lower part of the hot water storage tank 4, and a return hot water passage 17 for supplying hot water heated by the heat pump heat source device 3 to the hot water storage tank 4 is connected to the hot water storage tank. 4, a circulation heating passage 15 through which hot water can circulate between the hot water storage tank 4 and the heat pump heat source device 3 is formed.

The incoming hot water passage 16 is connected with an incoming water temperature sensor 18 for detecting the incoming water temperature of the hot water entering the heat pump heat source device 3 from the hot water storage tank 4, a circulation pump 19, and a switching valve 20. A heating temperature sensor 21 for detecting the temperature of hot water heated by the heat pump heat source device 3 is connected to the return hot water passage 17, and a bypass passage 22 connecting the outgoing hot water passage 16 and the return hot water passage 17 is provided. A switching valve 20 is connected to the connecting portion between the forward hot water passage 16 and the bypass passage 22 . When the heating temperature is low immediately after starting the heat pump heat source device 3, the switching valve 20 is switched to send the hot water heated by the heat pump heat source device 3 again to the heat pump heat source device 3 for reheating.

A plurality of stored hot water temperature sensors 4a to 4d for detecting the temperature of stored hot water are provided on the outer periphery of the hot water storage tank 4 at predetermined intervals in the vertical direction. These hot water temperature sensors 4a to 4d and hot water tank 4 are covered with a heat insulating material (not shown). An outlet hot water temperature sensor 7 a for detecting the outlet temperature of the hot water supplied to the hot water mixing valve 10 is connected to the hot water outlet passage 7 . A water supply temperature sensor 8a is connected to the water supply passage 8 for detecting the temperature of the water supply supplied from the water supply source. On the downstream side of the hot water mixing valve 10 in the hot water supply passage 11, a flow meter 11b for detecting the flow rate of hot water to be supplied and a hot water supply temperature sensor 11a for detecting the temperature of the hot water supply are connected.

An auxiliary heating passage 23 for heating the hot water in the hot water storage tank 4 with the auxiliary heat source machine 5 is branched from the hot water discharge passage 7 and connected to the auxiliary heat source machine 5 . An auxiliary hot water discharge passage 24 for discharging hot water heated by the auxiliary heat source machine 5 is connected via a regulating valve 25 to the hot water discharge passage 7 on the downstream side of the branch of the auxiliary heating passage 23 . A temperature sensor 24 a is provided in the auxiliary hot water outlet passage 24 .
The adjustment valve 25 adjusts the flow rate of hot water supplied to the hot water outlet passage 7 through the auxiliary hot water outlet passage 24 . A three-way valve 26 and a pump 27 for sending hot water to the auxiliary heat source machine 5 are interposed in the auxiliary heating passage 23 .

A heat exchange passage 28 branched from the auxiliary hot water discharge passage 24 is connected to a three-way valve 26 . The three-way valve 26 is switched so that hot water in the hot water storage tank 4 or hot water in the heat exchange passage 28 can be supplied to the auxiliary heat source device 5 . A heat exchanger 29, an on-off valve 30, and a temperature sensor 28a are interposed in the heat exchange passage 28. As shown in FIG. The heat exchanger 29 is used for a reheating operation in which the hot water in the bathtub 6 flowing through the reheating passage 12 is heated by heat exchange with the hot water heated by the auxiliary heat source device 5 by the operation of the reheating pump 31 .

The water supply passage 8 is connected to a check valve 32 and a branch passage portion 33 branched from the water supply passage 8 and connected to the heat exchange passage 28 . A check valve 34 is interposed in the bypass passage 9, and a high temperature discharge avoidance solenoid valve 36 is interposed in a high temperature discharge avoidance passage 35 branched from the bypass passage 9 and connected to the hot water supply passage 11. - 特許庁The various devices (pumps, valves, sensors) described above are electrically connected to the controller 43 and controlled by the controller 43 .

The heat pump heat source device 3 includes a heat pump circuit in which a compressor 37 , a condensing heat exchanger 38 , an expansion valve 39 , and an evaporative heat exchanger 40 are connected by refrigerant pipes 41 . The heat pump heat source device 3 compresses the refrigerant enclosed in the refrigerant pipe 41 by the compressor 37 to raise the temperature, drives the circulation pump 19, and heats the hot water flowing through the circulation heating circuit 15 to a high temperature in the condensation heat exchanger 38. heat by heat exchange with the refrigerant. After the heat exchange, the refrigerant expands in the expansion valve 39 to have a lower temperature than the outside air, absorbs heat from the outside air in the evaporative heat exchanger 40, and is introduced into the compressor 37 again.

The evaporative heat exchanger 40 includes an outside air temperature sensor 40a for detecting outside air temperature and a blower 40b. The heat pump heat source device 3 includes an auxiliary control section 42 that controls the compressor 37, the expansion valve 39, the blower 40b, and the like. The auxiliary control unit 42 is communicably connected to the control unit 43 and controls the heat pump heat source device 3 according to commands from the control unit 43 and others. The outside air temperature detected by the outside air temperature sensor 40 a is transmitted to the control section 43 via the auxiliary control section 42 .

Next, various controls employed in this hot water storage and hot water supply apparatus 1 will be described.
In this hot water storage and hot water supply apparatus 1, the future hot water consumption amount is predicted by learning and storing the hot water supply usage state, and before using the hot water supply, the heat pump heat source device 3 is driven to store the heat amount corresponding to the predicted hot water consumption amount. Store in a tank. The flow charts described below are stored in the control unit 43, and symbols Si (i=1, 2, . . . ) in the flow charts indicate steps.

This learning memory (hot water supply consumption data acquisition control) will be described with reference to FIGS. 2, 3, and 5. FIG.
In FIG. 2, the hot water supply consumption data acquisition control is a control that is always executed while the hot water storage and hot water supply apparatus 1 is in operation. When this hot water usage amount data acquisition control is started, various signals are read from the sensors in S1, and next, in S2, hot water usage amount data is calculated in time series every 60 minutes.
The amount of hot water supply is calculated through calorie calculation using the data detected by the temperature sensors 24a, 7a, 11a, 28a and the flow meter 11b. Next, in S3, the data of the amount of hot water supply used every 60 minutes is stored in a predetermined memory in association with the date, day of the week, and time zone, and the above S1 to S3 are repeatedly executed.

Next, hot water storage operation control will be described with reference to FIGS. 3 and 5. FIG.
When this hot water storage operation control is started, in S10, hot water consumption data for one day corresponding to the day of the week last week is read from the memory, and in S11, based on the hot water consumption data read in S10, Estimated hot water consumption for every 60 minutes is calculated for one day for each time zone. For example, as shown in FIG. 5, a predicted hot water usage amount similar to the hot water usage amount is calculated.

Next, in S12, a hot water storage operation schedule for every 60 minutes for one day is created based on the estimated amount of hot water supply used every 60 minutes. This is a hot water storage operation schedule for storing the predicted hot water consumption amount for each 60 minutes just before the hot water supply (for example, one hour ahead).

For example, as shown in FIG. 5, a schedule of hot water storage operating hot water amount is calculated by moving the predicted hot water consumption amount forward by one hour. Next, in S13, it is determined whether or not it is time for the hot water storage operation based on the hot water storage operation schedule. Next, in S15, it is determined whether or not the time is 24:00. When the determination is No, S13 to S15 are repeated, and when the determination in S15 becomes Yes, the control ends. Note that the hot water storage operation control may be started from 0:00 the next day without ending the control at 24:00.

Next, the equalization process performed when hot water is left in the hot water storage tank 4 at the end of hot water supply (for example, 24:00) on each day will be described with reference to FIG.
This equalization process estimates the temperature at which the temperature of the residual hot water in the hot water storage tank 4 will decrease due to heat radiation until the next hot water storage operation, and the estimated residual hot water temperature will be reduced by the auxiliary fuel during the next hot water storage operation. When the temperature reaches a temperature that requires reheating, this is a process for equalizing the temperature of the hot water in the hot water storage tank 4 .

When this control is started, it is determined whether or not there is residual hot water in the hot water storage tank at 24:00 (at the end of hot water supply for each day) in S20. This determination is made based on detection signals from the temperature sensors 4a to 4d of the hot water storage tank 4. FIG. If the determination in S20 is No, the control ends, and if the determination in S20 is Yes, the residual hot water temperature Tr is detected based on the detection signals of the temperature sensors 4a to 4d of the hot water storage tank 4 in S21.

Next, in S22, the standby time until the first hot water storage operation in the next morning is calculated, and the residual hot water temperature Ty in the next morning is estimated and calculated based on the standby time and the heat dissipation characteristics set in the hot water storage tank 4. . FIG. 6 is a time chart showing the standby time and the first hot water storage operation in the next morning.
It should be noted that the step of S22 and the control unit 43 correspond to residual temperature estimating means.

Next, in S23, it is determined whether or not the residual hot water temperature Ty is equal to or lower than the reheating necessary temperature (for example, 36° C. or lower) at which reheating by the auxiliary heat source device 5 is required. drives the pump 19 to circulate the hot water in the hot water storage tank 4 through the circulating heating passage 15 to agitate the hot water in the hot water storage tank 4 to equalize the temperature of the hot water (this is the homogenization of the temperature of the hot water). processing). This homogenization process is performed for a period of time sufficient to circulate about half of the total amount of hot water in the hot water storage tank 4 through the circulation heating passage 15, for example.

As described above, if the hot water in the hot water storage tank 4 is agitated and the temperature thereof is made uniform and the temperature is lowered, the COP of the heat pump heat source device 3 will be reduced when the heat pump heat source device 3 is operated to perform the hot water storage operation the next morning. can increase

That is, if there is residual hot water in the upper part of the hot water storage tank 4, and if it is not stirred, the low-temperature hot water in the lower part of the hot water storage tank 4 can be initially supplied to the heat pump heat source device 3 during the hot water storage operation in the next morning, thereby maintaining a high COP. Although it can be done, when medium-temperature residual hot water is supplied to the heat pump heat source device 3 after that, the COP of the heat pump heat source device 3 is significantly lowered, and the COP of the heat pump heat source device 3 as a whole is lowered. It is more advantageous to perform a homogenization process.

Next, in S25, it is determined whether or not the outside air temperature detected by the temperature sensor 40a is equal to or lower than the set temperature Ts (for example, 0°C). In the case of (2), a freeze prevention operation is performed to prevent freezing of the piping of the heating passage 15 by intermittently circulating the medium temperature hot water in the hot water storage tank 4 through the circulation heating passage 15 . Next, in S27, it is determined whether or not the first hot water supply operation in the next morning has been completed.

On the other hand, if the residual hot water temperature Ty in the next morning is higher than the reheating required temperature and the determination in S23 is No, it is determined in S28 whether or not the outside air temperature is equal to or lower than the set temperature Ts. When the determination in S28 is YES, the switching valve 20 is switched so that the forward hot water passage 16 and the bypass passage 22 are communicated, and the heat pump heat source device 3 and the pump 19 are intermittently driven to heat hot water. is circulated through the condensing heat exchanger 38, the return-side hot water passage 17, the bypass passage 22, and the going-side hot water passage 16 to perform a freeze prevention operation. Next, in S30, it is determined whether or not the first hot water supply operation in the next morning has been completed.

The operation and effects of the hot water storage and hot water supply apparatus 1 will be described.
As shown in FIG. 4, the temperature of the hot water remaining in the hot water storage tank 4 during the next hot water storage operation is estimated. 4, the temperature of the hot water in the hot water storage tank is uniformly lowered to prevent the COP of the heat pump heat source device 3 from decreasing during the next hot water storage operation. can be done. The homogenization process is performed by driving the circulation pump 19 to agitate the inside of the hot water storage tank 4 while the heat pump heat source 3 is not driven.

In addition, as shown in S26 in FIG. 4, when the outside temperature is low, the freeze prevention operation is performed to prevent the piping from freezing by circulating medium-temperature hot water of uniform temperature in the hot water storage tank 4. Since it is not necessary to operate the heat pump heat source machine 3 for freezing prevention, energy can be saved.

Further, when the residual hot water temperature Ty does not reach the temperature required for reheating in the next hot water storage operation, the temperature stratification in the hot water storage tank 4 can be maintained by omitting the equalization process.
In this case, as described in S29, the heat pump heat source unit 3 is intermittently driven and the bypass passage 22 is used to perform the freeze prevention operation in which hot water is circulated. can do.

Next, an example in which the above embodiment is partially modified will be described.
1] In the equalization process of FIG. 4, the step of S24 was executed immediately after 24:00 because of the anti-freezing operation. However, after several hours have passed since the execution of this specific operation, the high temperature water moves to the upper part and the low temperature water moves to the lower part, resulting in non-uniform hot water temperature.
Therefore, the same step as S24 may be repeated at the point immediately before the start of the first hot water storage operation in the next morning to equalize the temperature of the hot water in the hot water storage tank 4. FIG.

2] As conditions for executing S24, S24 is executed only when the amount of residual hot water is equal to or greater than a predetermined amount (for example, 1/3 of the volume of the hot water storage tank 4), and when the amount of residual hot water is equal to or less than the predetermined amount. In this case, the equalization process is not executed even if the determination in S23 is Yes.

That is, when the amount of residual hot water is less than a predetermined amount, the residual hot water is not reheated by the heat pump heat source device 3 during the next hot water storage operation. That is, even if the temperature of the hot water in the hot water storage tank 4 is made uniform by the equalization process, the temperature decrease due to the equalization is small, and the effect of preventing the COP of the heat pump heat source device 3 from decreasing cannot be expected so much. No processing shall be performed.

3) When a stirring means capable of stirring hot water in the hot water storage tank 4 (for example, a stirring blade rotated by a motor) is provided, the specific operation can be performed by driving the stirring means.
4] In addition, the present invention can be implemented by partially changing the above-described embodiment without departing from the gist of the present invention, and the present invention includes such modifications.

1 hot water storage device 2 hot water storage hot water supply unit 3 heat pump heat source device 4 hot water storage tank 5 auxiliary heat source device 15 circulation heating passage 19 circulation pump 37 compressor 38 condensation heat exchanger 39 expansion means 40 evaporative heat exchanger 43 control unit

Claims (4)

A heat pump heat source machine comprising a compressor, a condensing heat exchanger, an expansion means, and an evaporative heat exchanger connected by a refrigerant circuit, a hot water storage tank for storing hot water heated by the heat pump heat source machine, and the storage tank. A stored hot water supply having a circulation heating passage including a circulation pump for circulating hot water between a hot water tank and a heat pump heat source, and an auxiliary heat source for reheating and discharging hot water when the temperature of the hot water in the hot water storage tank drops. The device predicts the future amount of hot water supply by learning and storing the usage status of hot water supply, and drives a heat pump heat source device to store the amount of heat corresponding to the estimated amount of hot water supply in a hot water storage tank before using the hot water supply. In the hot water storage hot water supply device,
residual temperature estimating means for estimating a temperature in the case where the temperature of residual hot water in the hot water storage tank decreases due to heat radiation until the next hot water storage operation,
If the residual hot water temperature estimated by the residual temperature estimating means reaches a temperature at which reheating by the auxiliary heat source unit is required during the next hot water storage operation, a uniformization process is performed to equalize the temperature of the hot water in the hot water storage tank. In addition, when the outside air temperature is lower than the set temperature, the circulation pump is driven to circulate hot water as a freeze prevention operation for preventing freezing of the circulation heating passage,
The anti-freeze operation in the state where the homogenization process is performed performs circulation by the circulation heating passage in a passage configuration including the hot water storage tank, and the anti-freeze operation in the state where the homogenization process is not performed. A hot water storage and hot water supply apparatus characterized in that the hot water storage tank is bypassed and circulation is performed by the circulation heating path . 2. The hot water storage and hot water supply apparatus according to claim 1, wherein said homogenization process is performed by driving said circulation pump to agitate the inside of said hot water storage tank while said heat pump heat source is not driven. When the residual hot water is not heated by the heat pump heat source during the next hot water storage operation, the residual hot water temperature estimated by the residual temperature estimating means is the temperature at which reheating by the auxiliary heat source is required during the next hot water storage operation. 3. The hot water storage and hot water supply apparatus according to claim 1 or 2, wherein the equalization process is not performed for the hot water storage and hot water supply apparatus. The hot water storage and hot water supply apparatus according to any one of claims 1 to 3, wherein the equalization process is performed immediately before the next hot water storage operation is started.

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