JP6715948B2 - Water heater - Google Patents

Description

The present invention relates to a water heater, and more particularly to control of a water heater including a refrigerant circuit to which a water circulation circuit is connected.

For example, as a heat pump water heater, a heat pump water heater has been proposed that executes control to increase the number of rotations of a pump provided in a water circulation circuit stepwise when a boiling operation is started (for example, refer to Patent Document 1). By executing this control, the heat pump water heater of Patent Document 1 shortens the arrival time of the target hot water temperature and prevents the hot water discharge temperature from overshooting the target hot water temperature.

JP, 2005-140439, A

When the boiling operation is started, the temperature of the refrigerant, the operation of the device, and the like are not stabilized, and the COP (Coefficient Of Performance) of the water heater tends to decrease. When the boiling operation is started, the COP may be further decreased depending on the operation of various devices provided in the water heater. When starting the boiling operation, for example, if the rotational speed of the pump is suppressed too much, the COP may decrease more significantly.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a water heater capable of suppressing a decrease in COP.

A water heater according to the present invention, a compressor, a refrigerant circuit including a condenser connected to a water circulation circuit, a throttle device and an evaporator, and a tank provided in the water circulation circuit for storing water heated by the condenser. A conveying device that is provided in the water circulation circuit and conveys water to a tank of the water circulation circuit; a first detection unit that detects the outside air temperature; and a compressor and a throttle device based on the outside air temperature detected by the first detection unit. And a control device for controlling the transfer device, the control device including an operation control part for controlling operations of the compressor, the expansion device, and the transfer device, and the operation control part stores the heated water in the tank. When the boiling operation is started, both the compressor and the transport device are started together, and the compressor is kept in the first compression state until the predetermined first period elapses from the start of the boiling operation. After the first period has elapsed, the compressor is operated at the machine speed, and the compressor is operated at the second compressor speed, which is higher than the first compressor speed, and is determined in advance from the start of the boiling operation. The carrier device is operated at the first carrier rotation speed until the second period elapses, and after the second period elapses, the carrier device is operated at the second carrier rotation speed smaller than the first carrier rotation speed. Drive at .

Since the water heater according to the present invention has the above configuration, it is possible to suppress a decrease in COP.

It is a schematic structural example figure of the water heater 100 which concerns on embodiment. It is explanatory drawing of the boiling operation of the water heater 100 which concerns on embodiment. It is explanatory drawing of the additional cooking operation of the water heater 100 which concerns on embodiment. It is a functional block diagram of control device Cnt. It is a table with which the rotation speed of a compressor was specified with which control device Cnt is provided. It is a table provided with the control device Cnt, in which the transport rotation speed is specified. It is a table with which the 2nd period was specified with which control device Cnt is provided. It is a table with which the target hot water outlet temperature is specified, which is provided in the control device Cnt. It is a table with which the 3rd period was specified with which control device Cnt is provided. It is explanatory drawing of the time change of operation|movement of the compressor 1. It is explanatory drawing of the time change of operation|movement of the conveying apparatus 5. It is explanatory drawing of the time change of target tapped water temperature. It is a modification at the time of changing the setting rotation speed of the compressor 1 from a 1st compressor rotation speed to a 2nd compressor rotation speed.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that, in the following drawings including FIG. 1, the relationship of the sizes of the respective constituent members may be different from the actual one. In addition, in the following drawings including FIG. 1, the same reference numerals are the same or equivalent, and this is common to all the texts of the specification. Further, the forms of the constituent elements shown in the entire specification are merely examples, and the present invention is not limited to these descriptions.

Embodiment.
FIG. 1A is a schematic configuration example diagram of a water heater 100 according to the embodiment. The configuration of the water heater 100 will be described with reference to FIG. 1A.

[Structure description]
The water heater 100 includes a refrigerant circuit C1, a water circulation circuit C2, a control device Cnt, and various detection units. Further, the water heater 100 is connected to the hot water supply unit U1, the hot water supply unit U2, and the water supply unit U3. The hot water supply utilization unit U1 corresponds to, for example, a bath tub. Further, the hot water supply utilization unit U2 corresponds to, for example, a shower, a currant, a kitchen faucet, or the like. Further, the water supply unit U3 corresponds to, for example, a water tap connected to a water pipe.

The refrigerant circulates in the refrigerant circuit C1. A carbon dioxide refrigerant, for example, can be used as the refrigerant. The refrigerant circuit C1 includes a compressor 1 that compresses a refrigerant, a heat exchanger 2 that functions as a condenser, a throttle device 3 that has a function of reducing the pressure of the refrigerant, and a heat exchanger 4 that functions as an evaporator. The heat exchanger 4 is provided with a blower 4A that supplies air to the heat exchanger 4.
The heat exchanger 2 includes a refrigerant flow path through which a refrigerant flows and a water flow path through which water flows. The heat exchanger 2 is configured to exchange heat between the refrigerant flowing through the refrigerant flow path and the water flowing through the water flow path. The refrigerant circuit C1 is connected to the refrigerant passage of the heat exchanger 2, and the water circulation circuit C2 is connected to the water passage of the heat exchanger 2. The heat exchanger 2 condenses the refrigerant flowing through the refrigerant passage. The heat exchanger 2 can be configured by, for example, a double tube heat exchanger.

Water circulates in the water circulation circuit C2. The water circulation circuit C2 includes a water flow path of the heat exchanger 2, a flow path switching device 6A, a mixing circuit 6B, a tank 7 that stores water, a heat exchanger 8, and a flow path switching device 9. Further, water circulation circuit C2 includes a transport device 5 that transports water to tank 7, and a transport device 10 that transports water to hot water supply utilization unit U1. Further, the water circulation circuit C2 includes pipes P1 to P16. The transport device 5 and the transport device 10 can be configured by, for example, pumps that transport water.

The flow path switching device 6A can be composed of, for example, a four-way valve. The flow path switching device 6A includes four ports through which water flows. The flow path switching device 6A includes a first port a, a second port b, a third port c, and a fourth port d. The first port a of the flow path switching device 6A is connected to the pipe P3. The second port b of the flow path switching device 6A is connected to the pipe P4. The third port c of the flow path switching device 6A is connected to the pipe P2. The fourth port d of the flow path switching device 6A is connected to the pipe P8. The flow path switching device 6A can form a first flow path that connects the third port c and the fourth port d. Further, the flow path switching device 6A can form a second flow path that connects the first port a and the second port b. That is, the channel switching device 6A is configured to be capable of selectively switching between the first channel and the second channel.

The mixing circuit 6B is a circuit having a function of mixing heated water and water supplied from the water supply unit U3. The mixing circuit 6B includes a flow path switching device 6B1 and a flow path switching device 6B2. The flow path switching device 6B1 and the flow path switching device 6B2 can be configured by, for example, a three-way valve.
The flow path switching device 6B1 includes a first port a, a second port b, and a third port c. The flow path switching device 6B2 also includes a first port a, a second port b, and a third port c.

The first port a of the flow path switching device 6B1 is connected to the pipe P10. The second port b of the flow path switching device 6B1 is connected to the third port c of the flow path switching device 6B2. The third port c of the flow path switching device 6B1 is connected to the second port b of the flow path switching device 6B2. The first port a of the flow path switching device 6B2 is connected to the pipe P12. A pipe P11 is connected to a pipe connecting the second port b of the flow path switching device 6B1 and the third port c of the flow path switching device 6B2.

The tank 7 stores the water heated by the heat exchanger 2. The tank 7 is connected to the pipe P3, the pipe P5, the pipe P6, and the pipe P7.
The heat exchanger 8 includes a first water flow passage to which the pipes P8 and P9 are connected and a second water flow passage to which the pipes P12 and P13 are connected. The heat exchanger 2 is configured to exchange heat between the water flowing through the first water flow path and the water flowing through the second water flow path.

The flow path switching device 9 can be composed of, for example, a three-way valve. The flow path switching device 9 includes a first port a, a second port b, and a third port c. The first port a of the flow path switching device 9 is connected to the pipe P16. The second port b of the flow path switching device 9 is connected to the pipe P9. The third port c of the flow path switching device 9 is connected to the pipe P6. The flow path switching device 9 can form a third flow path that connects the first port a and the second port b. Moreover, the flow path switching device 9 can form a fourth flow path that connects the first port a and the third port c. That is, the flow path switching device 9 is configured to be able to selectively switch between the third flow path and the fourth flow path.

The pipe P1 connects the water discharge side of the transfer device 5 and the water flow path of the heat exchanger 2.
The pipe P2 connects the water flow path of the heat exchanger 2 and the third port c of the flow path switching device 6A.
The pipe P3 connects the first port a of the flow path switching device 6A and the tank 7.
The pipe P4 connects the second port b of the flow path switching device 6A and the pipe P1.
The pipe P5 connects the pipe P8 and the tank 7. Further, the pipe P5 connects the pipe P8 and the mixing circuit 6B.

The pipe P6 connects the tank 7 and the third port c of the flow path switching device 9.
The pipe P7 connects the tank 7 and the pipe P11.
The pipe P8 connects the fourth port d of the flow path switching device 6A and the pipe P5. The pipe P8 connects the fourth port d of the flow path switching device 6A and the first water flow path of the heat exchanger 8.
The pipe P9 connects the first water flow path of the heat exchanger 8 and the second port b of the flow path switching device 9.

The pipe P10 connects the hot water supply utilization unit U2 and the first port a of the flow path switching device 6B1 of the mixing circuit 6B.
The pipe P11 connects the water supply unit U3 and a pipe between the second port b of the flow path switching device 6B1 of the mixing circuit 6B and the third port c of the flow path switching device 6B2. The pipe P11 is connected to the pipe P7. Water is supplied to the mixing circuit 6B and the tank 7 through the pipe P11.

The pipe P12 connects the first port a of the flow path switching device 6B2 of the mixing circuit 6B and the second water flow path of the heat exchanger 8. The pipe P12 connects the first port a of the flow path switching device 6B2 of the mixing circuit 6B and the pipe P15.
The pipe P13 connects the water discharge side of the transfer device 10 and the second water flow path of the heat exchanger 8.
The pipe P14 connects the water intake side of the transfer device 10 and the hot water supply utilization unit U1.
The pipe P15 connects the pipe P12 and the hot water supply utilization unit U1.
The pipe P16 connects the water suction side of the carrier device 5 and the first port a of the flow path switching device 9.

The first detection unit 10A is a temperature sensor that detects the outside air temperature. The second detection unit 10B is a temperature sensor that detects the refrigerant temperature on the discharge side of the compressor 1. The third detection unit 10C is a temperature sensor that detects the temperature of the heat medium at the outlet of the heat exchanger 2.
The fourth detection unit 10D is a temperature sensor that detects the temperature of water stored in the tank 7. The fourth detection unit 10D can also be used to calculate the amount of water stored in the tank 7. The fourth detection unit 10D can be configured by, for example, a plurality of temperature sensors arranged in the vertical direction of the tank 7.

The detection results of the first detection unit 10A to the fourth detection unit 10D are output to the control device Cnt to control the compressor 1, the transfer device 5, the transfer device 10, and the like.

Each functional unit included in the control device Cnt is configured by dedicated hardware or an MPU (Micro Processing Unit) that executes a program stored in the memory. When the control device Cnt is dedicated hardware, the control device Cnt is, for example, a single circuit, a composite circuit, an ASIC (application specific integrated circuit), an FPGA (field-programmable gate array), or a combination thereof. Applicable Each of the functional units implemented by the control device Cnt may be implemented by individual hardware, or each functional unit may be implemented by a single piece of hardware. When the control device Cnt is an MPU, each function executed by the control device Cnt is realized by software, firmware, or a combination of software and firmware. Software and firmware are described as programs and stored in memory. The MPU realizes each function of the control device Cnt by reading and executing the program stored in the memory. The memory is, for example, a nonvolatile or volatile semiconductor memory such as a RAM, a ROM, a flash memory, an EPROM, and an EEPROM.

[Operation explanation]
FIG. 1B is an explanatory diagram of a boiling operation of the water heater 100 according to the embodiment.
The water heater 100 can execute a boiling operation in which water is boiled by the heat exchanger 2 and stored in the tank 7. During the boiling operation, the control device Cnt operates the compressor 1 to circulate the refrigerant in the refrigerant circuit C1. Here, at the start of the boiling operation, the control device Cnt sets the rotation speed of the compressor 1 to a first compressor rotation speed described later.
Further, during the boiling operation, the control device Cnt operates the transport device 5. Here, at the start of the boiling operation, the control device Cnt sets the rotation speed of the transfer device 5 to a first transfer rotation speed described later. During the boiling operation, the control device Cnt switches the flow channel switching device 6A to the first flow channel, and switches the flow channel switching device 9 to the fourth flow channel. As a result, the water in the water circulation circuit C2 flows in the order of the transfer device 5, the heat exchanger 2, the flow path switching device 6A, the tank 7, and the flow path switching device 9 and returns to the transfer device 5.

FIG. 1C is an explanatory diagram of an additional cooking operation of water heater 100 according to the embodiment.
The water heater 100 can also perform other operations than the boiling operation. Here, as an example, the additional cooking operation will be described.
The additional cooking operation is an operation of reheating the water stretched in the hot water supply utilization unit U1 (bath). In the additional cooking operation, the control device Cnt may stop the compressor 1 or may operate it. Further, in the additional cooking operation, the control device Cnt operates the transport device 5 and the transport device 10. Further, in the additional cooking operation, the control device Cnt switches the flow channel switching device 6A to the second flow channel, and switches the flow channel switching device 9 to the third flow channel. As a result, the water flowing out from the transport device 5 of the water circulation circuit C2 flows through the flow path switching device 6A, the tank 7, the heat exchanger 8 and the flow path switching device 9 and returns to the transport device 5. On the other hand, the water flowing out from the transport device 10 of the water circulation circuit C2 is heated by the water flowing through the first water flow path of the heat exchanger 8 and then supplied to the hot water supply utilization unit U1 via the pipe P15.

[Function of control device Cnt]
FIG. 2 is a functional block diagram of the control device Cnt.

The control device Cnt includes a heat amount acquisition unit 90A, a heat storage amount acquisition unit 90B, a first rotation speed acquisition unit 90C, and a second rotation speed acquisition unit 90D. Further, the control device Cnt includes a period acquisition unit 90E, a hot water outlet temperature information acquisition unit 90F, and an opening degree acquisition unit 90G. Further, the control device Cnt includes an operation control unit 90H and a storage unit 90I.

The heat amount acquisition unit 90A of the control device Cnt acquires data regarding the heat amount of water stored in the tank 7. The data relating to the heat quantity of water corresponds to the heat quantity of the residual hot water which is the heat quantity of the water in the tank 7. The heat amount acquisition unit 90A acquires the remaining hot water heat amount based on the temperature detected by the fourth detection unit 10D.

The heat storage amount acquisition unit 90B of the control device Cnt acquires data (target heat storage amount) regarding the target value of the total heat storage amount (total heat amount) of the water stored in the tank 7. The data related to the target value of the total heat storage amount of water corresponds to the target heat storage amount in the tank 7. The heat storage amount acquisition unit 90B calculates a target value of the total heat storage amount of water stored in the tank 7 based on, for example, the heat amount of water used in the hot water supply utilization unit U1, the hot water supply utilization unit U2, and the like. The heat storage amount acquisition unit 90B acquires the data regarding the calculated target value as the target heat storage amount.

The first rotation speed acquisition unit 90C of the control device Cnt acquires the first compressor rotation speed and the second compressor rotation speed based on the remaining hot water heat quantity, the target heat storage quantity, and the detected outside air temperature. .. The first rotation speed acquisition unit 90C acquires the residual hot water heat amount from the heat amount acquisition unit 90A, the target heat storage amount from the heat storage amount acquisition unit 90B, and the detected outside air temperature from the first detection unit 10A. The first compressor rotation speed and the second compressor rotation speed are predetermined constant values. Further, the second compressor rotation speed is higher than the first compressor rotation speed. Specific means for acquiring the first compressor rotation speed and the second compressor rotation speed will be described later with reference to FIG.

The second rotation speed acquisition unit 90D of the control device Cnt acquires the first transfer rotation speed and the second transfer rotation speed based on the remaining hot water heat quantity, the target heat storage quantity, and the detected outside air temperature. The second rotation speed acquisition unit 90D acquires the residual hot water heat amount from the heat amount acquisition unit 90A, the target heat storage amount from the heat storage amount acquisition unit 90B, and the detected outside air temperature from the first detection unit 10A. The first conveyance rotation speed is a predetermined constant value. On the other hand, the second conveyance rotation speed is not limited to a predetermined constant value and may be a variable value that changes with time. Further, the first transport rotation speed is lower than the second transport rotation speed. This magnitude relationship is satisfied regardless of whether the second conveyance rotation speed is a constant value or a fluctuation value. Specific means for acquiring the first transport rotation speed and the second transport rotation speed will be described later with reference to FIG. 4A.

The period acquisition unit 90E of the control device Cnt can acquire the first period previously stored in the storage unit 90I from the storage unit 90I.

Further, the period acquisition unit 90E acquires the second period based on the residual hot water amount, the target heat storage amount, and the detected outside air temperature. The period acquisition unit 90E acquires the residual hot water heat amount from the heat amount acquisition unit 90A, the target heat storage amount from the heat storage amount acquisition unit 90B, and the detected outside air temperature from the first detection unit 10A. A specific means for acquiring the second period will be described later with reference to FIG. 4B.

The hot water outlet temperature information acquisition unit 90F of the control device Cnt acquires the first target hot water temperature and the second target hot water temperature based on the remaining hot water amount, the target heat storage amount, and the detected outside air temperature. For example, when the detected outside air temperature becomes low as in winter, the first target hot water temperature and the second target hot water temperature are increased correspondingly. Hot water temperature information acquisition unit 90F acquires the detected outside air temperature from first detection unit 10A. Further, hot water outlet temperature information acquisition unit 90F acquires a third period in which the target hot water temperature is set to the first target hot water temperature based on the remaining hot water amount, the target heat storage amount, and the detected outside air temperature.

The opening degree acquisition unit 90G of the control device Cnt sets the first opening degree, which is the target opening degree of the expansion device 3, on the basis of the first compressor rotation speed and the target hot water discharge temperature at the start of the boiling operation. get. The opening degree acquisition unit 90G acquires the first compressor rotation speed from the first rotation speed acquisition unit 90C, and acquires the target hot water discharge temperature from the hot water discharge temperature information acquisition unit 90F. The opening degree acquisition unit 90G determines, based on the refrigerant temperature discharged from the compressor 1, a second opening degree that is the target opening degree of the expansion device 3 when a predetermined time has elapsed from the start of the boiling operation. Get the opening. That is, the opening degree acquisition unit 90G acquires the second opening degree based on the temperature detected by the second detection unit 10B.

The operation control unit 90H of the control device Cnt controls the rotation speed of the compressor 1, the opening degree of the expansion device 3, the rotation speed of the transfer device 5, and the rotation speed of the transfer device 10. Further, the operation control unit 90H switches the number of rotations of the blower 4A, the switching of the channels of the channel switching device 6A, the switching of the channels of the mixing circuit 6B (the channel switching device 6B1 and the channel switching device 6B2), and the flow. The switching of the flow path of the path switching device 9 is controlled.

Various data are stored in the storage unit 90I of the control device Cnt.

[Regarding the first compressor speed and the second compressor speed]
FIG. 3 is a table provided in the control device Cnt in which the number of rotations of the compressor is specified.
The control device Cnt includes a first table in which the first compressor rotation speed is specified and a second table in which the second compressor rotation speed is specified. In the first table and the second table, compressor rotation speeds that satisfy the following relationships are specified.

In the first table, a plurality of heat quantity difference values corresponding to the difference between the target heat storage quantity in the tank 7 and the residual hot water quantity which is the heat quantity of the water in the tank 7 are specified. The larger the difference between the target heat storage amount in the tank 7 and the remaining hot water amount which is the heat amount of the water in the tank 7, the larger the heat amount difference value. Here, the heat quantity difference value can be defined by a numerical value determined based on the difference between the target heat storage quantity in the tank 7 and the residual hot water quantity which is the heat quantity of the water in the tank 7. For example, if the difference between the target heat storage amount in the tank 7 and the residual hot water heat amount, which is the heat amount of water in the tank 7, is a numerical value within a predetermined first range, the heat amount difference value is 0. That is, in this case, the control device Cnt refers to the cell in the column of “0” in the first table of FIG. Further, for example, if the difference between the target heat storage amount in the tank 7 and the residual hot water heat amount that is the heat amount of the water in the tank 7 is a numerical value within a predetermined second range that is larger than the first range. The calorific value difference is 100. That is, in this case, the control device Cnt refers to the cell in the column “100” of the first table of FIG. Here, as an example, five different heat quantity difference values are specified.
Further, in the first table, a plurality of outside air temperature values corresponding to the detected outside air temperature are specified. Here, the outside air temperature value can be defined by a numerical value determined based on the detected outside air temperature. For example, if the detected outside air temperature is 40 degrees or lower and higher than 25 degrees, the outside air temperature value is 40. That is, in this case, the control device Cnt refers to the cell in the row of “40” in the first table of FIG. Further, for example, if the detected outside air temperature is 25 degrees or less and is higher than 16 degrees, the outside air temperature value is 25. That is, in this case, the control device Cnt refers to the cell in the row of “25” in the first table of FIG. Here, as an example, six different outside air temperature values are specified. Therefore, 5×6=30 first compressor rotation speeds are specified in the first table. Note that the third table, the fourth table, the fifth table, the sixth table, the seventh table, and the eighth table, which will be described below with reference to FIGS. 4A, 4B, 5A, and 5B. Also has the same format as the first table. That is, also in each of these tables, a plurality of heat amount difference values (for example, five) corresponding to the difference between the target heat storage amount in the tank 7 and the remaining hot water amount which is the heat amount of the water in the tank 7 is specified, and A plurality of (for example, six) outside air temperature values corresponding to the detected outside air temperature are specified. 4A, 4B, 5A, and 5B, the definitions of the heat quantity difference value and the outside air temperature value and the description of the heat quantity difference value and the outside air temperature value described based on FIG. 3 are applied. be able to.

The first compressor rotation speed increases as the difference between the target heat storage amount in the tank 7 and the residual hot water heat amount, which is the heat amount of water in the tank 7, increases. That is, when the outside air temperature value is constant, the first compressor rotation speed increases as the heat quantity difference value increases. This means that, when the outside air temperature value is constant, the first compressor rotation speed specified on the right side of the first table has a larger value.

Further, the first compressor rotation speed increases as the detected outside air temperature decreases. That is, when the calorific value difference is constant, the first compressor rotation speed increases as the outside air temperature value decreases. In the case where the calorific value difference value is constant, the value is larger as the first compressor rotation speed is specified on the lower side of the first table.

In the second table, the second compressor rotation speed is specified in the same manner as the first table. In the second table, a plurality of heat quantity difference values corresponding to the difference between the target heat storage quantity in the tank 7 and the residual hot water quantity which is the heat quantity of the water in the tank 7 are specified. Here, as an example, five different heat quantity difference values are specified. Further, a plurality of outside air temperature values corresponding to the detected outside air temperature are specified in the second table. Here, as an example, eight different outside air temperature values are specified. Therefore, in the second table, 5×8=40 second compressor rotation speeds are specified.

The second compressor rotation speed increases as the difference between the target heat storage amount in the tank 7 and the residual hot water heat amount, which is the heat amount of water in the tank 7, increases. That is, when the outside air temperature value is constant, the second compressor rotation speed increases as the heat quantity difference value increases.
Further, the second compressor rotation speed increases as the detected outside air temperature decreases. That is, when the calorific value difference is constant, the second compressor rotation speed increases as the outside air temperature value decreases.

During the period immediately after the start of the boiling operation, it is difficult to increase the efficiency of converting the work of the compressor 1 into the heat quantity of the water stored in the tank 7. This is because at the beginning of the boiling operation, the temperature of the refrigerant and the operation of various devices are not stable. Therefore, when starting the boiling operation, the control device Cnt suppresses the rotation speed of the compressor 1 as the first compressor rotation speed, and after the lapse of the first period, changes the rotation speed of the compressor 1 to the second rotation speed. By executing the control for increasing the rotation speed of the compressor, it is possible to suppress the decrease in COP.

For each compressor rotation speed specified in the first table and the second table, a numerical value that can improve the COP of the water heater 100 under various circumstances is adopted. In the embodiment, various conditions are determined based on the detected outside air temperature and the difference between the target heat storage amount and the residual hot water amount. In the embodiment, the situation of 5×8=40 is assumed. Since the control device Cnt operates the compressor 1 at the compressor rotation speed according to each situation, the water heater 100 can realize the boiling operation with high COP even under various situations.

[Regarding First Transport Rotational Speed and Second Transport Rotational Speed]
FIG. 4A is a table provided in the control device Cnt in which the transport rotation speed is specified.
The control device Cnt includes a third table in which the first transport rotation speed is specified and a fourth table in which the second transport rotation speed is specified. In the third table and the fourth table, the transport rotation speeds that satisfy the following relationships are specified.

The first transport rotation speed is larger as the difference between the target heat storage amount in the tank 7 and the residual hot water amount which is the heat amount of water in the tank 7 is smaller. That is, when the outside air temperature value is constant, the first conveyance rotation speed increases as the heat quantity difference value decreases.
Further, the first conveyance rotation speed is higher as the detected outside air temperature is higher. That is, in the case where the calorific value difference value is constant, the first conveyance rotation speed increases as the outside air temperature value increases.

The second conveyance rotation speed is larger as the difference between the target heat storage amount in the tank 7 and the residual hot water amount which is the heat amount of water in the tank 7 is smaller. That is, when the outside air temperature value is constant, the second conveyance rotation speed increases as the heat quantity difference value decreases.
Further, the second conveyance rotation speed is higher as the detected outside air temperature is higher. That is, when the calorific value difference value is constant, the second conveyance rotation speed increases as the outside air temperature value increases.

FIG. 4B is a table provided in the control device Cnt in which the second period is specified.
The control device Cnt includes a fifth table in which the second period is specified. In the fifth table, the second period satisfying the following relationship is specified.

The second period is shorter as the difference between the target heat storage amount in the tank 7 and the residual hot water amount which is the heat amount of water in the tank 7 is smaller. That is, when the outside air temperature value is constant, the second period becomes shorter as the heat quantity difference value is smaller.
The second period is shorter as the detected outside air temperature is higher. That is, when the heat quantity difference value is constant, the second period becomes shorter as the outside air temperature value becomes higher.

When the second transport rotation speed is a variable value, the control device Cnt acquires the initial value of the second transport rotation speed based on the residual hot water amount, the target heat storage amount, and the detected outside air temperature. Then, when the predetermined condition is satisfied, the control device Cnt executes, for example, a variation control for varying the transport rotation speed to vary the second transport rotation speed. As the variation control, for example, PID control (Proportional-Integral-Differential Controller) can be adopted. The PID control is not the only option, and P control or PI control may be used. Here, the predetermined condition can be, for example, that the temperature detected by the third detection unit 10C (hot water temperature) exceeds a predetermined target hot water temperature. That is, the control device Cnt shifts to the fluctuation control when the temperature detected by the third detection unit 10C (hot water temperature) exceeds the first target hot water temperature or the second target hot water temperature. As a result, the rotation speed of the transport device 5 changes from the initial value of the second transport rotation speed.

When the efficiency of obtaining the amount of heat supplied from the refrigerant circuit C1 is reduced if the number of rotations of the carrier device 5 is suppressed or the carrier device 5 is kept stopped during the period immediately after the start of the boiling operation. There is. That is, it is difficult to increase the efficiency of converting the work of the compressor 1 into the heat quantity of the water stored in the tank 7. Therefore, when the controller Cnt starts the operation of the compressor 1 and the operation of the carrier device 5 when starting the boiling operation, it is possible to suppress the decrease in the COP of the water heater 100.

For each pump rotation speed specified in the third table and the fourth table, a numerical value that can improve the COP of the water heater 100 under various circumstances is adopted. Even in the period specified in the fifth table, a numerical value that can improve the COP of the water heater 100 is adopted under various circumstances. In the embodiment, various situations are determined based on the detected outside air temperature and the difference between the target heat storage amount and the remaining hot water heat amount. In the embodiment, the situation of 5×8=40 is assumed. Since the control device Cnt operates the transport device 5 in the pump rotation speed according to each situation and the second period according to each situation, the water heater 100 has a high COP even under various conditions, and the boiling operation is performed. Can be realized.

[Regarding the first target hot water outlet temperature and the second target hot water outlet temperature]
FIG. 5A is a table provided in the control device Cnt in which the target hot water outlet temperature is specified.
The control device Cnt has a sixth table in which the first target hot water temperature is specified and a seventh table in which the second target hot water temperature is specified. In the sixth table and the seventh table, the first target hot water temperature and the second target hot water temperature that satisfy the following relationships are specified.

The first target hot water outlet temperature is higher as the difference between the target heat storage amount in the tank 7 and the residual hot water heat amount, which is the heat amount of water in the tank 7, is larger. That is, when the outside air temperature value is constant, the first target hot water outlet temperature is higher as the calorific value difference value is larger.
The first target hot water temperature is higher as the detected outside air temperature is lower. That is, when the calorific value difference value is constant, the first target hot water outlet temperature is higher as the outside air temperature value is smaller.

The second target hot water outlet temperature is higher as the difference between the target heat storage amount in tank 7 and the residual hot water heat amount, which is the heat amount of water in tank 7, is larger. That is, when the outside air temperature value is constant, the second target hot water temperature is higher as the calorific value difference value is larger.
The second target hot water temperature is higher as the detected outside air temperature is lower. That is, when the calorific value difference value is constant, the second target hot water outlet temperature is higher as the outside air temperature value is smaller.

FIG. 5B is a table provided in the control device Cnt in which the third period is specified.
The control device Cnt includes an eighth table in which the third period is specified. In the eighth table, the third period satisfying the following relationship is specified.

The third period is longer as the difference between the target heat storage amount in the tank 7 and the residual hot water amount which is the heat amount of water in the tank 7 is larger. That is, when the outside air temperature value is constant, the third period becomes longer as the calorific value difference value increases.
The third period is longer as the detected outside air temperature is lower. That is, when the calorie difference value is constant, the third period becomes longer as the outside air temperature value becomes lower.

Here, the effect will be described taking winter as an example. When the target hot water discharge temperature (corresponding to the first target hot water discharge temperature) is suppressed during a period immediately after the start of the boiling operation, the opening degree of the expansion device 3 becomes too large and the refrigerant discharged from the compressor 1 is discharged. The temperature may not rise easily, and the COP of the water heater 100 may decrease. Therefore, when the control device Cnt starts the boiling operation, the COP of the water heater 100 can be suppressed by setting the target hot water temperature in consideration of the detected outside air temperature. Further, when starting the boiling operation, the control device Cnt sets the target hot water outlet temperature in consideration of the difference between the target heat storage amount and the residual hot water heat amount, thereby suppressing a decrease in COP of the water heater 100. be able to.

As the target hot water outlet temperatures specified in the sixth table and the seventh table, numerical values that can improve the COP of the water heater 100 under various conditions are adopted. Even in the period specified in the eighth table, a numerical value that can improve the COP of the water heater 100 is adopted under various circumstances. In the embodiment, various situations are determined based on the detected outside air temperature and the difference between the target heat storage amount and the remaining hot water heat amount. In the embodiment, the situation of 5×8=40 is assumed. By setting the target hot water outlet temperature according to each situation and the third period according to each situation, control device Cnt can realize boiling operation with high COP even in various situations.

[Operation of the compressor 1 in the boiling operation]
FIG. 6A is an explanatory diagram of the time change of the operation of the compressor 1.
The time t=0 in FIG. 6A corresponds to the start of the boiling operation.
Further, the time t=t1 in FIG. 6A corresponds to the end of the first period of the boiling operation.
The compressor 1 operates at the first compressor rotation speed during the first period. Then, after the lapse of the first period, the compressor 1 operates at the second compressor rotation speed that is higher than the first compressor rotation speed.

[Operation of the transport device 5 in the boiling operation]
FIG. 6B is an explanatory diagram of the time change of the operation of the transport device 5.
The time t=0 in FIG. 6B corresponds to the start of the boiling operation.
Further, the time t=t2-1 in FIG. 6B corresponds to the end of the second period of the boiling operation.
Further, time t=t2-2 in FIG. 6B corresponds to the time when the temperature detected by the third detection unit 10C (hot water temperature) exceeds the first target hot water temperature. Note that FIG. 6B shows an example in which the second period is shorter than the third period.
The transfer device 5 operates at the first transfer rotation speed during the second period. Then, when the second period elapses, the transport device 5 starts the operation at the second transport rotation speed smaller than the first transport rotation speed. When the temperature detected by the third detection unit 10C (hot water temperature) exceeds the first target hot water temperature, the rotation speed of the transport device 5 changes from the second transport rotation speed.

[Change in target hot water temperature with time during boiling operation]
FIG. 6C is an explanatory diagram of the change over time of the target hot water outlet temperature.
The time t=0 in FIG. 6C corresponds to the start of the boiling operation.
Further, time t=t3 in FIG. 6C corresponds to the end of the third period of the boiling operation.
The control device Cnt sets the set value of the target hot water outlet temperature to the first target hot water outlet temperature during the third period. Then, when the third period elapses, control device Cnt sets the set value of the target hot water outlet temperature to the second target hot water outlet temperature that is higher than the first target hot water outlet temperature.

FIG. 7 is a modification example in which the set rotation speed of the compressor 1 is changed from the first rotation speed of the compressor to the second rotation speed of the compressor. At the end of the first period, the control device Cnt may gradually increase the set rotation speed of the compressor 1 from the first compressor rotation speed to reach the second compressor rotation speed. .. The same applies to the operation of the carrier device 5.

DESCRIPTION OF SYMBOLS 1 compressor, 2 heat exchanger, 3 throttling device, 4 heat exchanger, 4A blower, 5 conveying device, 6A flow path switching device, 6B mixing circuit, 6B1 flow path switching device, 6B2 flow path switching device, 7 tank, 8 heat exchanger, 9 flow path switching device, 10 transfer device, 10A first detection unit, 10B second detection unit, 10C third detection unit, 10D fourth detection unit, 90A heat amount acquisition unit, 90B heat storage Quantity acquisition unit, 90C first rotation speed acquisition unit, 90D second rotation speed acquisition unit, 90E period acquisition unit, 90F hot water outlet temperature information acquisition unit, 90G opening degree acquisition unit, 90H operation control unit, 90I storage unit, 100 Water heater, C1 refrigerant circuit, C2 water circulation circuit, Cnt control device, P1 pipe, P2 pipe, P3 pipe, P4 pipe, P5 pipe, P6 pipe, P7 pipe, P8 pipe, P9 pipe, P10 pipe, P11 pipe, P12 pipe , P13 pipe, P14 pipe, P15 pipe, P16 pipe, U1 hot water supply utilization part, U2 hot water supply utilization part, U3 water supply part.

Claims (16)

A compressor, a refrigerant circuit including a condenser connected to a water circulation circuit, a throttle device and an evaporator,
A tank provided in the water circulation circuit for storing water heated by the condenser;
A transport device that is provided in the water circulation circuit and transports water to the tank of the water circulation circuit,
A first detector for detecting the outside air temperature;
A control device that controls the compressor, the expansion device, and the transfer device based on the outside air temperature detected by the first detection unit;
Equipped with
The control device is
Including an operation control unit that controls operations of the compressor, the expansion device, and the transfer device,
The operation control unit,
When starting a boiling operation for storing heated water in the tank, both the compressor and the transfer device are started together,
Until the predetermined first period elapses from the start of the boiling operation, the compressor is operated at the first compressor rotation speed,
After the lapse of the first period, the compressor is operated at a second compressor rotation speed higher than the first compressor rotation speed ,
From the start of the boiling operation until a predetermined second period elapses, the transfer device is operated at the first transfer rotation speed,
After the lapse of the second period, the water heater that operates the transport device at a second transport rotation speed that is lower than the first transport rotation speed . The first compressor speed is
The water heater according to claim 1, wherein the larger the difference between the target heat storage amount in the tank and the remaining hot water amount which is the heat amount of water in the tank, the larger. The second compressor speed is
The water heater according to claim 1 or 2, wherein the larger the difference between the target heat storage amount in the tank and the remaining hot water amount which is the heat amount of water in the tank, the larger. The first compressor speed is
The water heater according to any one of claims 1 to 3, wherein the lower the detected outside air temperature, the larger the detected outside air temperature. The second compressor speed is
The water heater according to any one of claims 1 to 4, wherein the lower the detected outside air temperature, the greater the detected outside air temperature. The first transport rotation speed is
As the difference between the remaining hot water heat is heat in the water target heat storage amount and the tank in the tank is small, the water heater according to any one of a large claims 1-5. The second conveyance rotation speed is
The water heater according to any one of claims 1 to 6 , wherein the smaller the difference between the target heat storage amount in the tank and the remaining hot water heat amount that is the heat amount of water in the tank, the larger. The first transport rotation speed is
The water heater according to any one of claims 1 to 7 , wherein the higher the detected outside air temperature, the larger. The second conveyance rotation speed is
The water heater according to any one of claims 1 to 8 , wherein the higher the detected outside air temperature, the larger. The second period is
The water heater according to any one of claims 1 to 9 , wherein the smaller the difference between the target heat storage amount in the tank and the remaining hot water heat amount that is the heat amount of water in the tank, the shorter the difference. The second period is
The water heater according to any one of claims 1 to 10 , wherein the higher the detected outside air temperature, the shorter. The control device is
The water heater according to any one of claims 1 to 11 , further comprising a heat quantity acquisition unit that acquires a residual hot water heat quantity that is the heat quantity of water in the tank. The control device is
Water heater according to any one of claims 1 to 12, further comprising a heat storage amount acquisition unit that acquires a target heat storage amount in the tank. The control device is
The first compressor rotation speed and the second compressor rotation speed are acquired based on the residual hot water heat quantity that is the heat quantity of water in the tank, the target heat storage quantity in the tank, and the detected outside air temperature. water heater according to any one of claims 1 to 13, further comprising a first rotation speed acquisition unit. The control device is
Second, the first transport rotation speed and the second transport rotation speed are acquired based on the residual hot water heat quantity that is the heat quantity of water in the tank, the target heat storage quantity in the tank, and the detected outside air temperature. The water heater according to any one of claims 1 to 14 , further comprising a rotation speed acquisition unit. The control device is
Based on the residual hot water heat quantity which is the heat quantity of water in the tank, the target heat storage quantity in the tank, and the detected outside air temperature, the second period in which the transfer device is operated at the first transfer rotation speed is set. The water heater according to any one of claims 1 to 15 , further comprising a period acquisition unit for acquiring.

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