JP2014095501A - Hot water supply device, and hot water supply system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To utilize dump power which cannot be sold without decreasing durability.SOLUTION: A hot water supply system 1 can operate a hot water supply device 5 by purchased electric power from a system 2 or by generated output generated with a sunlight panel 3. The hot water supply system 1 can sell the generated output to the system 2. When the generated output cannot be sold, surplus power is generated. A power conditioner 4 or a tank controller 11 sets available electric power based on the surplus power. A heat pump controller 12 decides and controls a target discharge temperature and a rotating speed of a compressor 14 so that a target boiling temperature is carried out based on an available electric power and under a restriction of the available electric power. A rotating speed of the compressor 14 is controlled by a feedforward control in startup. After having driven in an appointed time, feedback control of the rotating speed of the compressor 14 is performed based on the available electric power.

Description

  The present invention relates to a hot water supply apparatus that heats water by operating a refrigeration cycle driven by electric power as a heat pump and stores the heated water (hot water), and relates to electric power supplied from a premises power generation apparatus such as a solar power generation apparatus. It is related with the hot water supply apparatus which can perform heat pump operation by. Furthermore, the present invention relates to a hot water supply system including a hot water supply device and a premises power generation device.

  Patent Document 1 and Patent Document 2 disclose a hot water supply apparatus that heats water by operating a refrigeration cycle driven by electric power as a heat pump. This hot water supply apparatus includes a tank for storing heated water, that is, hot water. Further, the hot water supply device includes a control device that determines the compressor rotation speed based on the outside air temperature. Even if the heating capacity changes depending on the outside air temperature, this apparatus boils a required temperature and amount of hot water in the tank by the target time.

  Patent Document 3 proposes that a hot water supply device is operated by electric power generated by a premises power generation device such as a solar power generation device (solar cell). This device operates a hot water supply device when the voltage rise suppression of the power conditioner is activated, and can be used for solar power generation that can store excess power energy of solar power generation, which was previously a loss, as thermal energy. It is a water heater.

Japanese Patent No. 3737414 JP2012-2442A JP 2006-29635 A

  In the configuration of the prior art, the heat pump operation is performed in the daytime by supplying excess power to the hot water supply device. This device can reduce the amount of power used at midnight as much as possible by storing heat in the hot water supply device in the daytime with surplus power that cannot be sold when power can be generated. In addition, hot water is often used in front of midnight hours such as baths and showers, and hot water boiled in the daytime has a short heat storage time. For this reason, the heat radiation time at the time of tank heat storage is reduced, thereby saving energy overall.

  This device operates the hot water supply device when the voltage rise to suppress the power flow to the grid, that is, the voltage rise to suppress the voltage rise to sell power, operates the water heater. When the hot water supply operation is used, the voltage rise suppression does not work, and if the conditions for power sale are satisfied, it may be better to stop the hot water supply device (heat storage <power sale).

  In the conventional apparatus, when the hot water supply device is operated with a small surplus power, the operation / stop is repeated, and if the number of times is large, the durability of the device is lowered.

  The objective of this invention is providing the hot water supply apparatus which can utilize the surplus electric power which cannot be sold without reducing the durability of a hot water supply apparatus.

  Another object of the present invention is to provide a hot water supply apparatus that can suppress an increase in the number of times of operation / stop of the hot water supply apparatus (number of times of starting and stopping) in order to prevent a decrease in durability of the hot water supply apparatus.

  Still another object of the present invention is to boil at low capacity and low power consumption according to the available power, thereby reducing the amount of power used in the middle of the night while suppressing the increase in the number of on / off times. It is to provide a hot water supply device.

  One of the disclosed inventions employs the following technical means to achieve the above object. It should be noted that the reference numerals in parentheses described in the claims and in this section indicate a corresponding relationship with specific means described in the embodiments described later as one aspect, and are technical aspects of the disclosed invention. It does not limit the range.

  One of the disclosed inventions is a hot water storage tank (10), a water-refrigerant heat exchanger (15) that heats water supplied to the hot water storage tank, and an electric motor that compresses refrigerant supplied to the water refrigerant heat exchanger. A refrigeration cycle that can operate a heat pump, and a power that can be used by the compressor that is set based on surplus power that is generated by the on-site power generator (3) and cannot be sold to the grid (2) The target discharge temperature (Tb) and the target rotation speed of the compressor (14) are determined based on the possible electric power (Pow_aq, Php) and the outside air temperature (Tam) which is the temperature of the outside air as the heat source of the refrigeration cycle. And a control device (12) for controlling the hot water supply device.

  According to this configuration, usable power that can be used by the compressor is set. Based on the available power, the target discharge temperature and the rotation speed of the compressor are determined, and the compressor is controlled. Therefore, the refrigeration cycle can be operated under the restriction of usable power.

  One of the disclosed inventions is that the on-site power generation device (3), the purchased power (P1) purchased from the system (2), and the sold power (P2) for selling the generated power generated by the on-site power generation device to the system. ), A voltage sensor for detecting the voltage (Vb) of the purchased power as the system voltage of the system (2), a hot water storage tank (10), and water for heating the water supplied to the hot water storage tank A refrigerant heat exchanger (15) and an electric compressor (14) that compresses the refrigerant supplied to the water-refrigerant heat exchanger, a refrigeration cycle capable of operating a heat pump, and a system voltage (Vb) for the on-site power generator When it is higher than the upper limit value (Vlimit) of the generated voltage (V3) of the premises, it is determined that the on-site power generator can generate surplus power, and a control device (12) that operates the refrigeration cycle with surplus power is provided. Toss A hot water supply system.

  The control device is set based on surplus power that is generated by the on-site power generation device (3) and cannot be sold to the grid (2), and indicates usable power (Pow_aq, Php) indicating the power that can be used by the compressor, and a heat source of the refrigeration cycle The target discharge temperature (Tb) and the target rotation speed of the compressor (14) are determined based on the outside air temperature (Tam) that is the temperature of the outside air, and the compressor (14) is controlled.

1 is a block diagram illustrating a hot water supply system according to a first embodiment of the present invention. It is a block diagram which shows the heat pump unit of 1st Embodiment. It is a PH diagram which shows the characteristic of the heat pump of 1st Embodiment. It is a block diagram which shows the arithmetic processing of 1st Embodiment. It is a flowchart which shows the heat pump control process of 1st Embodiment. It is a wave form diagram which shows an example of the action | operation of 1st Embodiment. It is a wave form diagram which shows an example of the action | operation of 1st Embodiment. It is a graph which shows the control characteristic of 1st Embodiment. It is a graph which shows the control characteristic of 1st Embodiment. It is a block diagram which shows the electric power system of 1st Embodiment. It is a block diagram which shows the electric power system of 1st Embodiment. It is a wave form diagram which shows an example of the action | operation of 1st Embodiment. It is a flowchart which shows the electric power control process of 1st Embodiment. It is a wave form diagram which shows an example of the action | operation of 1st Embodiment. It is a wave form diagram which shows an example of the action | operation of 1st Embodiment. It is a wave form diagram which shows an example of the action | operation of 1st Embodiment. It is a graph which shows the operating characteristic of a comparative example. It is a graph which shows the operating characteristic of 1st Embodiment. It is a flowchart which shows the heat pump control process of 2nd Embodiment of this invention. It is a flowchart which shows the electric power control process of 3rd Embodiment of this invention. It is a flowchart which shows the electric power control process of 4th Embodiment of this invention. It is a flowchart which shows the power control process of 5th Embodiment of this invention. It is a circuit diagram which shows the determination circuit of the electric power which concerns on 5th Embodiment. It is a wave form diagram which shows an example of the action | operation of 6th Embodiment of this invention. It is a wave form diagram which shows an example of the action | operation of a comparative example. It is a wave form diagram which shows an example of the action | operation of 7th Embodiment of this invention.

  Hereinafter, a plurality of modes for carrying out the disclosed invention will be described with reference to the drawings. In each embodiment, parts corresponding to the matters described in the preceding embodiment may be denoted by the same reference numerals, and redundant description may be omitted. When only a part of the configuration is described in each mode, the other modes described above can be applied to the other parts of the configuration. Further, in the following embodiments, the correspondence corresponding to the matters corresponding to the matters described in the preceding embodiments is indicated by adding reference numerals that differ only by one hundred or more, and redundant description may be omitted. . Not only combinations of parts that clearly show that combinations are possible in each embodiment, but also combinations of the embodiments even if they are not explicitly stated unless there is a problem with the combination. Is also possible.

(First embodiment)
(Configuration of hot water supply system)
FIG. 1 is a configuration diagram of a hot water supply system 1 including an electric power system and a hot water supply apparatus. In the figure, the input / output relationship of some signals is shown. In this embodiment, the hot water supply system 1 is configured in a general house or a small business establishment.

  The hot water supply system 1 can receive power supply from the system 2. System 2 is commercial power provided from a wide area power network. The hot water supply system 1 includes a premises power generation device 3. The on-premises power generation device 3 is a small-scale power generation facility installed on the premises, and is provided by, for example, a solar panel 3 (solar power generation device).

  The hot water supply system 1 includes a power conditioner (hereinafter referred to as PWC) 4 installed between a system 2, a premises power generation device 3, and a load device including the hot water supply device 5. The PWC 4 can receive power from the grid 2. The PWC 4 can supply power to the grid 4. Such a function is called reverse power flow. The PWC 4 can receive power from the solar panel 3. The PWC 4 can execute maximum power control for controlling current and voltage so as to maximize the generated power in the solar panel 3. The PWC 4 can supply power from the system 2 and / or power from the solar panel 3 to the hot water supply device 5 that is a load device. The PWC 4 includes a plurality of AC / DC and DC / DC converter circuits, and provides power control such as power conversion, voltage adjustment, and power factor adjustment between devices connected to the PWC 4. The PWC 4 includes a controller configured by a microcomputer.

  The hot water supply device 5 includes a tank unit (hereinafter referred to as TKU) 6 and a heat pump unit (hereinafter referred to as HPU) 7. The TKU 6 includes a hot water storage tank 10 for storing hot water, and a tank controller (hereinafter referred to as “TKC”) 11 constituted by a microcomputer. The HPU 7 includes a refrigeration cycle and a heat pump controller (hereinafter referred to as HPC) 12 constituted by a microcomputer. The HPU 7 includes a motor 14 for driving a compressor of the refrigeration cycle, and an inverter circuit 13 for controlling the rotation speed of the motor 14.

  A plurality of controllers provided in the PWC 4, the TKU 6, and the HPU 7 provide a control device for the hot water supply device. The control device may be configured in a distributed manner by a plurality of controllers as in the embodiment, or may be configured in an integrated manner by two or one controller. The control device is an electronic control unit (Electronic Control Unit). The control device includes a processing device (CPU) and a memory (MMR) as a storage medium for storing a program. The control device is provided by a microcomputer including a computer-readable storage medium. The storage medium stores a computer-readable program non-temporarily. The storage medium can be provided by a semiconductor memory or a magnetic disk. By being executed by the control device, the program causes the control device to function as the device described in this specification, and causes the control device to function so as to execute the control method described in this specification. The means provided by the control device can also be called a functional block or module that achieves a predetermined function.

  The electric power generated by the solar panel 3 is input to the PWC 4. Power conversion is performed by the converter in the PWC 4. The direct current power (DC) generated by the solar panel 3 is converted into alternating current power (AC). The PWC 4 monitors the generated power from the solar panel 3 and the grid power from the grid 2. The PWC 4 switches whether to supply power to the load on the premises with generated power or with grid power. The PWC 4 can switch power supply to a plurality of or some loads. The PWC 4 controls the power supply so that the grid power is used when the generated power is small.

  The PWC 4 can supply the generated power to the grid 2 when the generated power is large. This is called reverse power flow or power selling. At this time, the hot water supply system 1 sells electric power to an electric power company. A voltage higher than the voltage of the system 2 is generated by the PWC 4 and output to the system 2, so that a current flows toward the system 2. Such a state can be called a state in which the PWC 4 can sell power.

  The PWC 4 includes a voltage increase suppression function that suppresses an increase in voltage in order to limit the output voltage to the allowable voltage of the load device or less when the voltage of the grid 2 is high even during power generation. In this case, power cannot be sold because current cannot flow to the system 2 side as the PWC 4. Such a state can be called a state in which the PWC 4 cannot sell power.

  When solar radiation for power generation is insufficient, such as at night, the solar panel 3 cannot generate sufficient power, for example, AC 200V. The PWC 4 supplies power to the load device using the system 2 when the solar panel 3 does not generate power. Such a state can be called a state in which the PWC 4 is in the power generation OFF state.

  Electric power is supplied from the PWC 4 to the hot water supply device 5. The PWC 4 supplies power to both the TKU 6 and the HPU 7. By communicating to the TKC 11 and the HPC 12 by communication about the power control state in the PWC 4, for example, whether the power is being sold by the generated power or the voltage is being suppressed, the hot water supply device 5 performs heat pump control according to the power control state, That is, load control is provided. In this embodiment, a power related signal including usable power is transmitted from the PWC 4 to the TKC 11 and further transmitted from the TKC 11 to the HPU 7. The usable power that can be used by the whole hot water supply device 5 may be transmitted from the PWC 4 to the TKC 11, and the usable power that can be used only by the HPU 7 may be transmitted from the TKC 11 to the HPU 7.

(Configuration of heat pump unit)
FIG. 2 shows the internal configuration of the HPU 7. The details of the configuration of the HPU 7 can be referred to Japanese Patent No. 3737414. In the figure, a refrigeration cycle circuit and a water circuit connected to the TKU 6 are shown. The A pipe 6 a communicates with the lower part of the hot water storage tank 10. Cold water is supplied from the hot water storage tank 10 to the HPU 7 by the A pipe 6a. The HPU 7 heats the water by operating the refrigeration cycle as a heat pump and returns the water from the B pipe 6 b to the hot water storage tank 10. The B pipe 6 b communicates with the upper part of the hot water storage tank 10. Heating water with HPU 7 is sometimes referred to as boiling. Between the A pipe 6a and the B pipe 6b, a water supply pump 21 for flowing water through the water circuit, a strainer 22 for filtering water, and a water-refrigerant heat exchanger 15 are provided.

  The refrigeration cycle is a supercritical refrigeration cycle using carbon dioxide as a refrigerant. The refrigeration cycle includes an electric compressor 14 that sucks and pressurizes low-pressure refrigerant and discharges the high-pressure refrigerant. The refrigeration cycle includes a water-refrigerant heat exchanger 15 disposed on the high pressure side. The water-refrigerant heat exchanger 15 may be referred to as a radiator, a condenser, a radiator, or a condenser in the refrigeration cycle. The water-refrigerant heat exchanger 15 is disposed on the discharge side of the compressor 14. The water-refrigerant heat exchanger 15 provides heat exchange between the high-temperature high-pressure refrigerant and the water flowing through the water circuit, and heats the water flowing through the water circuit with the high-temperature high-pressure refrigerant. The refrigeration cycle includes an expansion valve 16 disposed between the high pressure side and the low pressure side. The expansion valve 16 is disposed on the downstream side of the water-refrigerant heat exchanger 15. The expansion valve 16 is controlled such that a high pressure becomes a pressure necessary to achieve a necessary hot water temperature.

  The refrigeration cycle includes an air-refrigerant heat exchanger 17 disposed on the low pressure side. The air-refrigerant heat exchanger 17 may be referred to as a cooler, a heat sink, an evaporator, or an evaporator in a refrigeration cycle. The air-refrigerant heat exchanger 17 is disposed on the downstream side of the expansion valve 16. The air-refrigerant heat exchanger 17 provides heat exchange between the low-temperature low-pressure refrigerant and the outside air, and allows the low-temperature low-pressure refrigerant to absorb the heat of the outside air. The HPU 7 includes a fan motor 18 for generating an air flow that passes through the air-refrigerant heat exchanger 17. The refrigeration cycle includes an accumulator 19 that is disposed between the air-refrigerant heat exchanger 17 and the compressor 14 and stores excess refrigerant.

  The HPU 7 includes a plurality of sensors 31-38 for controlling the refrigeration cycle. The HPU 7 includes a refrigerant outlet thermistor 31 that is installed in the vicinity of the refrigerant outlet of the water-refrigerant heat exchanger 15 and detects the temperature of the refrigerant (exit temperature). The HPU 7 includes a pressure sensor 32 that is installed in the high-pressure portion of the refrigeration cycle, in the illustrated example, between the water-refrigerant heat exchanger 15 and the expansion valve 16 and detects the pressure (high-pressure) of the refrigerant. The HPU 7 includes an evaporator inlet thermistor 33 that detects the refrigerant temperature (inlet temperature) in the vicinity of the inlet of the air-refrigerant heat exchanger 17. The HPU 7 includes a frost thermistor 34 that detects the temperature of the refrigerant (outlet temperature) in the vicinity of the outlet of the air-refrigerant heat exchanger 17. The frost thermistor 34 is also a sensor for detecting the amount of frost attached to the outer surface of the air-refrigerant heat exchanger 17. The HPU 7 includes an outside air thermistor 35 that detects the temperature of the air passing through the air-refrigerant heat exchanger 17 (outside air temperature). The HPU 7 is provided in the vicinity of the refrigerant outlet of the compressor 14 and includes a discharge temperature thermistor 36 that detects the temperature (discharge temperature) of the refrigerant.

  The HPU 7 is provided in the vicinity of the water outlet of the water-refrigerant heat exchanger 15 and includes a boiling thermistor 37 for detecting the temperature of the hot water after boiling (boiling temperature). The HPU 7 is provided in the vicinity of the water inlet of the water-refrigerant heat exchanger 15 and includes a water supply thermistor 38 that detects the temperature of the water before boiling (water supply temperature Twi).

  The refrigeration cycle is a refrigeration cycle that can be operated by a heat pump, and is an electric motor that compresses the water-refrigerant heat exchanger 15 that heats water supplied to the hot water storage tank 10 and the refrigerant that is supplied to the water-refrigerant heat exchanger. At least the compressor 14 is included.

(Control of heat pump unit)
FIG. 3 is a PH diagram showing operating characteristics of the refrigeration cycle provided in the HPU 7. The horizontal axis represents enthalpy (kJ / kg), and the vertical axis represents pressure (MPa). In the figure, a saturated vapor diagram ST1, an isothermal line ST2 of temperature Ta, an isentropic line ST3, an isothermal line ST4 of temperature Tb, and an isovolumetric line ST5 are shown. The temperature Ta is the temperature on the suction side of the compressor 14. The refrigerant state between the accumulator 19 and the compressor 14 in FIG. 2 is shown. The temperature Tb is the temperature on the discharge side of the compressor 14 and represents the state of the refrigerant at the position of the discharge temperature thermistor 36.

  The refrigeration cycle can be modeled based on the PH diagram. Some variables indicating the operating state of the refrigeration cycle can be detected by a sensor. By controlling the components of the refrigeration cycle based on the detected values and the mathematical model, the refrigeration cycle can be controlled to a desired operating state while accurately grasping the operating state of the refrigeration cycle. In this embodiment, the power consumption L and the heating capacity Q are estimated from the outside air temperature Tam, the feed water temperature Twi, and the target boiling temperature Tp, and the control target element of the HPU 7 is controlled based on these.

The refrigerant circulation flow rate G (kg / h) is given by G = Vc / Vs = Vc · V. However, V1 (cc): Cylinder volume of the compressor 14, η: Volume efficiency, N (rpm): Rotational speed of the compressor 14, V (kg / m ³ ): Equivalent volume, Vs: Specific volume (m ³ / kg ) (Vs = 1 / V). The power consumption L (kJ) is given by L = (ib−ia) · G. The suction volume Vc (kg / m ³ ) of the compressor 14 is given by Vc = ((V1 · N · 60) / 10 ⁶ ) · η. The power consumption L can be rewritten as L = (ib−ia) · Vc · V = ((V1 · N · 60) / 10 ⁶ ) · η · V · (ib−ia). The compressor rotation speed N (rpm) can be rewritten as N = L · 10 ⁶ / (V1 · V · 60 · η · (ib−ia)). In actual calculation processing, usable power may be received in units of kW. In this case, the coefficient Kj = 2.777778 × 10 ⁻⁴ can be used for unit conversion from kJ to kW · h. In this case, the compressor rotation speed N (rpm) can be rewritten as N = (L / Kj) · 10 ⁶ / (V1 · V · 60 · η · (ib−ia)).

  FIG. 4 is a block diagram for obtaining the heating capacity Q and the required power L by arithmetic processing. Necessary power L = power consumption. The power consumption is obtained based on the rotation speed N of the compressor 14, the suction point enthalpy ia of the compressor 14, and the discharge point enthalpy ib of the compressor 14. The cylinder volume V1 and volume efficiency η of the compressor 14 are determined in advance as the characteristics of the compressor 14. Therefore, three necessary variables are the rotation speed N, enthalpy ia, and enthalpy ib.

From the cylinder volume V1, the volume efficiency η, and the rotational speed N, the suction volume Vc of the compressor 14 is obtained by Vc = (V1 × N × 60) / 10 ⁶ × η. The specific volume Vs is obtained based on the enthalpy ia and the mathematical formula determined from the PH diagram. From the suction volume Vc and the specific volume Vs, the refrigerant circulation flow rate G is obtained by G = Vc / Vs. From the refrigerant circulation flow rate G, the condenser outlet enthalpy ic, that is, the enthalpy ic at the refrigerant outlet of the water-refrigerant heat exchanger 15, and the discharge point enthalpy ib of the compressor 14, the heating capacity Q is Q = (ic−ib) It is obtained by × G × Cc. From the refrigerant circulation flow rate G, the discharge point enthalpy ib of the compressor 14, and the suction point enthalpy ia of the compressor 14, the required power L, that is, the power consumption L is obtained by L = (ib−ia) × G × Cc.

  FIG. 5 shows a control process 150 for the HPC 12 to control the refrigeration cycle. Based on the available power, the HPC 12 controls a plurality of control target elements of the HPU 7 so that the boiling temperature Tp necessary for storing the hot water in the hot water storage tank 10 within the limit of the available power can be realized. For example, the HPC 12 controls the compressor 14, the expansion valve 16, and the feed water pump 21 of the refrigeration cycle. The HPC 12 controls the control target element so that the compressor 14 is operated for a long time with usable electric power that is significantly less than that during normal operation in which hot water is stored in the hot water storage tank 10 by midnight electric power. The HPC 12 allows the refrigeration cycle to be operated at a lower efficiency than during normal operation in which the refrigeration cycle is controlled to achieve high efficiency.

  The HPC 12 provides a control device. The HPC 12 determines the target discharge temperature and target rotation speed of the compressor 14 and controls the compressor 14. The HPC 12 is usable power Pow_aq, Php indicating the power that can be used by the compressor 14 that is set based on surplus power that is generated by the on-site power generator 3 and cannot be sold to the grid 2, and is the temperature of the outside air as a heat source of the refrigeration cycle. Based on the outside air temperature Tam, the target boiling temperature Tp, and the feed water temperature Twi which is the temperature of the feed water, the target discharge temperature and the target rotation speed are determined.

  In step 151, the outside air temperature Tam and the feed water temperature Twi are input from the sensors 35 and 38. In step 152, the target boiling temperature Tp and the usable power Pow_aq are received from the TKU 6. The HPC 12 adjusts the rotation speed N of the compressor 14 to be controlled so as not to exceed the usable power Pow_aq. The symbol Pow_aq is attached to the usable power used in the control processing in the HPC 12.

  In step 153, it is determined whether or not the HPU 7 is activated. If it is determined that the HPU 7 is activated, the process proceeds to step 154. If it is determined that the HPU 7 is not activated, the process proceeds to step 159.

  In step 154, the refrigerant inlet temperature Ta at the inlet of the compressor 14 is estimated. The inlet temperature Ta is obtained from the outside air temperature Tam by Ta = Tam + Ct1. The constant Ct1 can be set to −10 (° C.), for example. The inlet temperature Ta corresponds to the intersection of the isotherm ST2 and the saturated vapor line ST1 in the PH diagram.

  In step 155, the refrigerant outlet temperature Tb at the outlet of the compressor 14 is estimated. The outlet temperature Tb is obtained from the target boiling temperature Tp by Tb = Tp + Ct2. The constant Ct2 can be set to +10 (° C.), for example. The outlet temperature Tb corresponds to the intersection of the isentropic line ST3 and the isothermal line ST4 in the PH diagram. In the case of Tp = 65 (° C.), Tb = 75 (° C.) is estimated. The outlet temperature Tb is also called a target discharge temperature. Therefore, the target discharge temperature Tb is set as a value obtained by adding the predetermined value Ct2 to the target boiling temperature Tp.

  In step 156, enthalpies ia and ib are obtained based on the inlet temperature Ta and the outlet temperature Tb. The enthalpies ia and ib are obtained based on the PH diagram. As illustrated, the value on the horizontal axis indicates enthalpy.

  Thus, in this embodiment, in order to estimate the required electric power, the enthalpy ib of the refrigerant at the outlet of the compressor 14 is approximated from the target boiling temperature Tp. Further, the enthalpy ia of the refrigerant at the suction port of the compressor 14 is estimated from the outside temperature Tam.

In step 157, the specific volume Vs (kg / m ³ ) is obtained from the specific volume line ST5 passing through the inlet temperature Ta.

In step 158, the target compressor speed N is calculated from the available power Pow_aq. Step 158 sets a target compressor rotational speed N that can achieve the target boiling temperature Tp by feedforward (F / F) control. The target compressor rotational speed N for the feedforward control can be obtained from the right equation, N = (L / Kj) · 106 / (V1 · V · 60 · η · (ib−ia)). L is power and Kj is a unit conversion coefficient from kJ to kW · h. The unit of the target compressor speed N is rpm. In the above equation, usable power Pow_aq is substituted for power L, and Kj = 2.77778 × 10 ⁻⁴ is substituted.

  In step 159, start-up time for operating the HPU 7 and periodic monitoring for feedback (F / B) control are executed. In step 159, it is determined whether the startup time for starting the HPU 7 from the stopped state and continuing the operation has elapsed. Further, after activation, in step 159, it is determined whether or not a time corresponding to a control cycle for feedback control has elapsed. If the activation time or the control cycle has not elapsed, the control process 150 is repeated by jumping to the subsequent step. If it is the first time after the activation time has elapsed, or if the control period has elapsed after the activation time has elapsed, the process branches to YES and proceeds to step 160.

  In step 160, power is estimated from the actual consumption current of the electric compressor 14, and feedback control is performed to adjust the target compressor rotational speed N so that the actual consumption power matches the available power Pow_aq. In step 160, the current consumption can be detected by the function of the inverter 13.

  In step 158 and step 160, the opening degree of the expansion valve 16 and the rotation speed of the feed water pump 21 are controlled together with the rotation speed of the compressor 14. These are controlled to achieve the target boiling temperature Tp.

  According to this embodiment, at the start of operation of the HPU 7, that is, at the beginning of startup, the control target element of the HPU 7 is feedforward controlled based on the initial value. After the feed forward control for a predetermined time, the control target element is feedback controlled.

  The HPC 12 provides a means (step 154) for estimating the refrigerant enthalpy ib at the outlet of the compressor 14 from the target boiling temperature Tp. The HPC 12 provides means (step 155) for estimating the refrigerant enthalpy ia in the intake of the compressor 14 from the outside air temperature Tam. Further, the HPC 12 provides means (step 158) for determining the target discharge temperature and the target rotation speed based on the plurality of enthalpies ia and ib.

  FIG. 6 shows an example of the operation by the control process 150. The refrigeration cycle control in step 158 and step 160 is control for determining the target discharge temperature Tb and the target compressor speed N. The motor of the compressor 14 is controlled to reach the target compressor speed N. The compressor 14 is controlled so that its actual rotational speed becomes the target compressor rotational speed N.

  In the illustrated example, the HPU 7 is activated from time t1. The compressor 14 is feedforward controlled between time t1 and time t2. As a result, the rotational speed of the compressor 14 gradually increases to the target compressor rotational speed N. The target compressor speed N is an initial value. The initial value may be a fixed value or a variable value that is variable based on conditions such as the outside air temperature at the start of operation. After time t2, the first feedback control is executed. Subsequent feedback control is performed after time t3. As a result, the rotation speed of the compressor 14 is controlled so that the power consumption Pnow substantially matches the available power Pow_aq. The power consumption Pnow is given by Pnow = 200 (V) × IDC × Cpf. Here, IDC is a current consumption that can be detected by the inverter 13. Cpf is a predetermined coefficient, for example, a power factor coefficient, and can be set to 0.8, for example.

  FIG. 7 shows an example of the operation by the control process 150. In the illustrated example, the HPU 7 is activated from time t1. The compressor 14 is feedforward controlled between time t1 and time t3. As a result, the rotational speed of the compressor 14 increases to the target compressor rotational speed N, and is maintained at the target compressor rotational speed N until the start-up time elapses. In the initial period of the startup period, the opening degree of the expansion valve 16 is set to an initial value. As the high pressure increases, the refrigerant outlet temperature Tco at the outlet of the compressor 14 gradually increases. After time t3, the rotation speed of the compressor 14 is feedback-controlled.

  FIG. 8 shows control characteristics for feedback control of the compressor 14. The horizontal axis indicates the difference ΔP, and the vertical axis indicates the rotation amount adjustment amount ΔN. In the feedback control, the rotation speed of the compressor 14 is controlled so that the difference ΔP (ΔP = Pow_aq−Pnow) between the current actual power consumption Pnow and the usable power Pow_aq approaches 0 (zero). However, in the vicinity of ΔP = 0, a dead band having a predetermined width for stabilizing the control is set.

  Returning to FIG. 7, when the HPU 7 is activated and a predetermined time elapses, the opening degree of the expansion valve 16 is feedback-controlled from time t2. The opening degree Oem of the expansion valve 16 is feedback controlled after time t2. The HPC 12 controls the expansion valve opening degree Oem so that the refrigerant outlet temperature at the outlet of the compressor 14, that is, the discharge temperature Tco becomes the target discharge temperature Tb.

  When the operation of the HPU 7 is started, the expansion valve opening degree Oem is controlled by a fixed value given as an initial value. Control by the initial value is continued for a predetermined F / F control time, and the expansion valve opening degree Oem is maintained. After time t2, the expansion valve opening degree Oem is F / B controlled. At this time, the difference ΔTco (ΔTco = Tb−Tco) is positive, and if it is large, the expansion valve 16 is adjusted by a predetermined amount in the valve closing direction. In other words, the expansion valve 16 is driven to the negative side of the valve opening degree Oem. When the discharge temperature Tco exceeds the target discharge temperature Tb, the difference ΔOe is negative. In this case, the expansion valve 16 is adjusted by a predetermined amount toward the valve opening side.

  FIG. 9 shows control characteristics for feedback control of the expansion valve 16. The horizontal axis indicates the difference ΔTco, and the change amount ΔOe of the opening degree Oem. In the feedback control, the opening degree Oem of the expansion valve 16 is controlled so that the difference ΔTco between the discharge temperature Tco and the target discharge temperature Tb approaches 0 (zero). However, in the vicinity of ΔTco = 0, a dead zone having a predetermined width for stabilizing the control is set. The opening degree Oem is controlled within the range of the maximum value OemMAX and the minimum value OemMIN. For example, OemMIN = 60step and OemMAX = 500step can be set.

  Returning to FIG. 7 again, after time t3, both the compressor 14 and the expansion valve 16 are feedback-controlled. The rotation speed of the compressor 14 is controlled so that the power consumption Pnow is lower than the usable power Pow_aq, and the power consumption Pnow is close to the usable power Pow_aq. The opening degree Oem of the expansion valve 16 is such that the outlet temperature of the compressor 14, that is, the discharge temperature Tco becomes the target discharge temperature Tb, in other words, the discharge temperature Tb necessary to achieve the target boiling temperature Tp is obtained. To be controlled. At the same time, the HPC 12 controls the amount of water supply by controlling the rotation speed of the water supply pump 21 so that the target boiling temperature Tp is obtained. As a result, the target boiling temperature Tp can be obtained by operating the refrigeration cycle within the limit range of the usable power Pow_aq.

(Power system configuration)
FIG. 10 shows an electrical relationship between the grid 2 and a plurality of consumers. In the figure, the direction of power flow in power purchase and the direction of power flow in power sale are indicated by arrows. The electric power in the power sale is also surplus electric power in each consumer. As shown in the figure, solar panels may be installed in neighboring houses belonging to the grid 2. In this description, A house 1a is assumed to be a consumer provided with the hot water supply system according to the present embodiment, and B house 1b is assumed to be a consumer provided with a solar panel. The grid | system 2 supplies electric power to a some consumer via the transformer, for example, the pole transformer 2b, from the substation 2a. The transformer 2 b is the nearest transformer closest to the hot water supply system 1 in the system 2. The number of consumers belonging to one transformer is set by a power supply company or the like. In the illustrated example, electric power is supplied from one pole transformer 2b to two consumers. The pole transformer 2b outputs the system voltage Vb to the secondary side, that is, the customer side. The system voltage Vb is also called an output voltage Vho on the secondary side of the columnar transformer 2b.

  The solar panel 3 of the A house 1a outputs the generated voltage Vm. The PWC 4 has a converter function for converting DC power obtained from the solar panel 3 into AC power. The generated voltage Vm may be converted into alternating current by a DC / AC converter (converter) provided in the PWC 4 and supplied to the system 2 in some cases. When power is supplied to the grid 2, that is, when selling power, the PWC 4 adjusts the frequency and voltage of the output power in order to maintain the power supply characteristics and quality of the grid 2 supplied from the power company. For example, the output power is adjusted to 50 or 60 Hz, 100V or 200V.

  The PWC 4 supplies a voltage higher than the normal system voltage to the system 2. For example, if the voltage during normal operation, nighttime, and no power generation is 200 VAC, the PWC 4 boosts the voltage for power sales during the daytime power generation. By boosting, the PWC 4 outputs, for example, a voltage of AC 202V + 20V to the system 2 when selling power, that is, when surplus power is generated. In order to sell electricity, the output voltage is adjusted to be higher than the system voltage Vb and the output voltage Vho. When selling power from both A house 1a and B house 1b, the output voltage from each consumer increases. A house 1a needs to consider the output voltage VbB of B house 1b.

  In order to sell electricity, there is also a method of reducing the output voltage of the transformer. In this case, the output voltage of the transformer is adjusted by the power supply company or the power transmission company. There is also a method of raising a specified value (voltage suppression value) of PWC. In this case, the adjustment is performed by the construction contractor or the manufacturer of the PWC 4 according to the demand of the consumer. In addition, there is a method in which a consumer provides an original transformer between the system 2 and the customer. In this case, the consumer bears the cost of the transformer.

  FIG. 11 shows a detailed view of the device configuration. In the drawing, a plurality of power sensors are shown in order to show the flow of power in the A house 1a which is one consumer. The electric power supplied from the electric power company is supplied to consumers through pole transformers. A power sensor P1 for detecting the power consumed by the A home 1a is provided on the power line connecting the A home 1a and the system 2. The power sensor P1 is also called a load wattmeter. The power sensor P1 can be provided by a power meter installed to calculate a power charge. The direction of the current flowing toward the A house 1a of the power sensor P1 is defined as (+). The (+) direction is the power used. The power measured by the power sensor P1 is also referred to as used power P1. The used power P1 indicates power purchase.

  When a current is supplied to the grid 2 by power generation in the A house 1a, a reverse power flow occurs. The reverse flow current is measured as (−) in the power sensor P1. This value is also called power sales because the surplus of power generation is sold to the power company. The absolute value of the power when the power sensor P1 indicates (−) is also referred to as power selling power P2. Therefore, when the indicated value of the power sensor P1 is smaller than 0, that is, when it indicates a negative (−) value, the sold power P2 is expressed as P2 = −P1. The sold power P2 may be detected by a reverse power flow sensor P2 that detects power flowing from the A house 1a toward the grid 2.

  A generated power sensor P3 for detecting the generated power P3 is provided between the solar panel 3 and the PWC 4. The power generated by the solar panel 3 and adjusted in frequency, voltage, and phase by the PWC 4 is detected as the generated power P3.

  A load power sensor P4 for detecting the load power P4 is provided between all electric loads belonging to the A house 1a and the PWC 4. The amount of power consumed by the load is detected as a load power amount P4.

  The surplus power can be obtained by comparing the generated power P3 and the load power P4. When the power generation amount exceeds the load amount (P3> P4), surplus power may be generated. When loss and the like are not taken into account, the difference between the generated power P3 and the load power P4 becomes surplus power, and the surplus power can be sold. Conversely, when P3 <P4, it is necessary to purchase P1 = P4-P3 in order to purchase from the system 2 the power that is insufficient to supply the load power P4.

  By inputting the signals of the power sensors P1, P3, and P4 to the PWC 4 or the hot water supply device 5, by operating the refrigeration cycle as much as the surplus power, the surplus power energy is effectively used, and the surplus power energy Can be stored by changing into the energy of the amount of heat of the hot water (represented by the amount of hot water and temperature). For example, the usable power of the HPU 7 that is a load is configured to be instructed to the HPU 7 from the PWC 4 or TKU 6, that is, the host system device viewed from the HPU 7, and hot water can be stored using surplus power.

  Next, the mechanism of power sales will be explained. When the generated power P3 generated by the solar panel 3 (solar power generation facility) is larger than the load power P4 of the A house 1a, surplus power can be sold. At this time, the PWC 4 needs to output at a voltage higher than the system voltage Vb. When the generated voltage Vm exceeds the system voltage Vb (Vm> Vb), it may be considered that a reverse power flow is generated and power can be sold. However, the output voltage Vho is determined by the transformer of system 2 as the voltage for selling power, and Vho≈Vb when there is no power sale from other consumers.

  Here, when surplus power is generated in the B house 1b and can be sold, the B house 1b also tries to output a voltage higher than the output voltage Vho of the transformer. When B home 1b outputs power selling voltage VbB, B home 1b can sell power when VbB> Vho. At this time, when the power generation voltage Vm of the home A 1a is smaller than the power selling voltage VbB of the home B 1b, the output voltage Vho of the transformer 2b becomes higher than the power selling voltage VbB due to the capacity of the transformer. At this time, if the system voltage Vb is Vb <Vm, the A house 1a can also be sold. However, when Vb ≧ Vm, power cannot be sold from the A house 1a.

  Even if there is a competition for power sale with such a nearby consumer, the PWC 4 increases the generated voltage Vm to the voltage suppression value so as not to waste surplus power. If Vb <Vm can be established by boosting to the voltage suppression value, power can be sold from the home A 1a.

  If the generated voltage Vm does not exceed the system voltage Vb even though the voltage is boosted to the voltage suppression value of PWC4, that is, if Vb <Vm does not hold, the surplus power generated from the A home 1a cannot be sold. It becomes useless. In this embodiment, the surplus power is used to operate the HPU 7 to utilize the surplus power. In other words, in this embodiment, when the power cannot be sold, the generated power P3 is effectively utilized by increasing the power consumption P4 of the A house 1a.

  The hot water supply system 1 includes power sensors P1 and P2 that detect purchased power P1 purchased from the system 2 and sold power P2 that sells the generated power generated by the on-premises power generation device 3 to the system 2. The hot water supply system 1 includes a voltage sensor that detects the voltage Vb of the purchased power as the system voltage Vb of the system 2 in the PWC 4.

(Power system behavior)
FIG. 12 shows an example of an operation following the change in the generated power P3. In the figure, the purchased power P1, the used power P4, the sold power P2, the generated power P3, the operating state (ON / OFF) of the HPU 7, and changes in the usable power usable by the HPU 7 are illustrated. The figure shows a case where the purchased power P1 is not generated.

  In the example shown in the figure, the power generation amount has decreased due to changes in weather such as cloudy from time t1. Although the amount of power generation falls, the amount of power generation still remains. However, when a nearby customer sells power, the voltage of the grid 2 increases, and thus power cannot be sold. For example, A home 1a cannot sell power because B home 1b sells power. Such a state is indicated by symbol I in the figure.

  At this time, surplus power is generated in the A house 1a. When the generation of surplus power is stabilized in the state indicated by the symbol I, the operation of the HPU 7 is started from time t2 using this surplus power. Here, the generated power P3 exceeds 0.5 kW, but 0.5 kW less than the generated power P3 is set as usable power. Thereby, even if there exists a fluctuation | variation of generated electric power P3, the fluctuation | variation of usable electric power is suppressed.

  Eventually, when the power sale becomes possible, the power sale is resumed and the operation of the HPU 7 is stopped. This behavior is illustrated in the figure by the symbol II. The case where the generated power P3 increases to the extent that power can be sold is shown. In the state indicated by symbol II, it is determined that the power sale can be stably continued. For users, it may be desirable to sell electricity when comparing the increase in revenue from selling electricity with the reduction in payment due to the suppression of late-night electricity usage by storing hot water. For example, this is a case where the power price of power sale exceeds the power price of power purchase. In the example shown in the figure, due to such a background, power selling is started prior to time t3, and the HPU 7 is stopped at time t3.

  In addition, in the state of connection when operating the HPU 7 with surplus power from the time when the power was sold, even if some power purchase occurs, if the power purchase is short, to the user that the electricity bill will increase It is considered that there is little adverse effect. As shown in the figure, the power sale suddenly becomes zero, and if the load power on the premises cannot be covered by surplus power, power purchase is made. However, even if the power cannot be sold, it can be supplied by the generated power P3.

(Control processing for available power)
FIG. 13 shows a control process 170 for setting usable power and instructing the HPC 12. This control process 170 is executed by a controller provided in the PWC 4 or the TKU 6. This control processing 170 determines whether or not to operate the HPU 7 when there is surplus power, and instructs the HPU 7 on the amount of power that can be used. The control process 170 is a process for instructing the daytime usable power from the on-premises power system, that is, the PWC 4 or the TKC 11 to the HPC 12. When the system voltage Vb is higher than the upper limit value Vlimit of the power generation voltage V3 of the local power generation device 3, the HPC 12 determines that the local power generation device 3 can generate surplus power and operates the refrigeration cycle using the surplus power.

  In step 171, information necessary for processing is input from a plurality of sensors and control devices. For example, power P1-P4 is input from a plurality of power sensors. Further, the voltage Vb of the system 2, that is, the voltage of the distribution system is input. This voltage Vb is an effective value.

  In step 172, the voltage suppression value Vlimit in PWC4 is input from PWC4. The PWC 4 boosts the voltage of power supplied to the grid 2 for selling power, and its upper limit value is the voltage suppression value Vlimit.

  In step 173, a determination is made when there is surplus power when power cannot be sold. This determination is affirmative when all the following three conditions are satisfied, and branches to YES. If at least one condition is not satisfied, a negative determination is made and the process branches to NO. The first condition is whether or not the system voltage Vb exceeds the voltage suppression value Vlimit (Vb> Vlimit). This indicates that power cannot be sold even if the voltage is increased. The second condition is that there is no actual power sale performance (P2≈0 kW). The third condition is that the hot water storage state in the tank 10 can be increased in the next midnight time zone, and hot water can be additionally stored from the current tank hot water storage amount. That is, the third condition is that the inside of the tank 10 is not filled with high-temperature hot water and heat can be further stored in the tank 10. If all the above three conditions are met, the process branches to YES assuming that the HPU 7 can be operated. If at least one condition is not satisfied, the process branches to NO.

  If YES in step 173, the process proceeds to step 174. In step 174, it is determined whether or not the first boiling operation using surplus power, that is, the first excessive boiling operation. If it is the first time, the process proceeds to step 175. In step 175, the available power Php is set to the lowest value Php_min that can be raised. For example, the minimum value Php_min can be set to 0.5 kW.

  If it is determined in step 174 that it is not the first time, the process proceeds to step 176. After the operation of the HPU 7 continues, the process branches from step 174 to step 176. In step 176, it is determined whether or not a predetermined time has elapsed from the update timing of the available power Php. The predetermined time can be, for example, 30 minutes.

  If an affirmative determination is made in step 176, the process proceeds to step 177. In step 177, it is determined whether or not there is power purchase (P1> 0). If the amount of power generation is large and there is no power purchase, the process proceeds to step 178. In step 178, the available power Php is added. Here, the new available power Php (n) is obtained by adding a predetermined value, for example, 0.1 kW to the previous available power Php (n−1).

  If there is power purchase in step 177 (P1> 0), the available power Php is held. If the predetermined time has not elapsed in step 176, the available power Php is maintained.

  If branched to NO in step 173, the process proceeds to step 180. In step 180, the HPU 7 boiling operation is stopped. At the same time, the usable power Php is set to 0.0 kW.

  In step 179, the determined available power Php is transmitted to the HPU 7 by communication. The HPC 12 of the HPU 7 controls the operation of the refrigeration cycle of the HPU 7 according to the available power Php. The HPC 12 determines whether the refrigeration cycle operation is ON / OFF based on the available power Php, and when the operation is ON, that is, when operating, operates the refrigeration cycle within the available power Php and supplies hot water to the hot water storage tank 10. The refrigeration cycle is controlled so as to store hot water at the temperature required.

  The HPC 12 operates the hot water supply device before it becomes surplus power without being able to sell electricity, and makes it possible to sell power at any time using surplus power, so that it can store hot water with surplus power and store electricity with solar power generation. To perform more efficient control. Conventionally, hot water is stored mainly with midnight power, but it can be boiled with surplus power in power generation. However, when boiling water with the conventional capacity and power consumption, the generated power may be consumed in excess, so the system side is instructed to the HPU 7 the usable power that can be used as hot water supply, and boiling within the usable power. Raise. The HPU 7 not only simply limits power consumption but also preferentially sets control target values for a plurality of actuators included in the HPU 7 by executing a process of setting usable power from available power in advance. Control is performed by

(Setting example of usable power)
FIG. 14 shows an operation example when the usable power Pow_aq is set. As shown in the figure, from time t1, the power generation voltage V3 is raised to the voltage suppression value Vlimit by the PWC4. If power cannot still be sold, surplus power determination is executed during a predetermined time between time t2 and time t3. As a result, when it is determined that the surplus voltage is stably generated, the available power Pow_aq is increased from time t3, and the operation of the HPU 7 is started. Eventually, the generated power P3 further increases, and when the stable generation of surplus power is determined again during the surplus determination period T3 between time t4 and time t5, the available power Pow_aq is further increased from time t5. The

  In this embodiment, the control is executed based on the recognition that the available power Pow_aq is not actually used unless it is used. The surplus power varies depending on the performance of the solar panel 3, how the sun shines, and the weather. Therefore, the power generation voltage V3 is boosted for power sale from time t1. If power generation does not occur even when the generated voltage V3 is boosted to the voltage suppression value Vlimit, if the state is detected for a certain period of time, the HPU 7 is operated because it is desired to use the surplus power to boil hot water. The presence / absence of power sale can be determined based on the purchased power P1. When P1 ≧ 0, there is no power sale. When P1> 0, the power is being purchased. After the time t3, the controller belonging to the system side, that is, the PWC 4 or the TKC 11 instructs the HPC 12 of the usable power Pow_aq and starts the boiling operation. In the figure, usable power Pow_aq of 0.5 kW is illustrated.

  When the power consumption P4 in the A home 1a before the HPU 7 is operated is monitored, when P1 = 0 indicating that there is no power purchase, if the boiling operation is executed, the increase in power consumption ΔP3 of the HPU 7 Therefore, the power consumption of the entire home, that is, the load power P4 increases. In the illustrated example, when the boiling operation is executed within the usable power Pow_aq limit in the HPU 7, ΔP3 = 0.5 kW and P4 = 0.6 kW.

  Here, when the surplus power stability is continuously determined during the surplus determination period T3 for determining the stability of power consumption after the available power is updated, the available power Pow_aq is added. . The stability of the surplus power can be determined by, for example, establishment of a condition of P3max−P3min <0.05 kW. In the illustrated example, a predetermined value of 0.1 kW is added to the usable power Pow_aq. The added value here is set so that the usable power Pow_aq is equal to or less than the maximum usable power value Pow_aqMAX. The reason why the predetermined power of 0.1 kW is added to the usable power Pow_aq is to determine how much surplus power can be secured by power generation and to search for the maximum value of the usable power Pow_aq. Therefore, if the stable state continues, the addition is continued up to the maximum usable power value Pow_aqMAX.

  The maximum usable power value Pow_aqMAX can be determined as follows. In this embodiment, since the available power Pow_aq uses surplus power, the maximum usable power value Pow_aqMAX can be the maximum amount of power generation or the maximum power consumption of the HPU 7. However, HPU7 has a rating. Therefore, there is no problem in making hot water if the rated power consumption in normal operation using power in the midnight time zone, which is a basic function of the HPU 7, is set to the maximum usable power value Pow_aqMAX. For example, when the heating capacity that the HPU 7 can exhibit is 4.5 kW and the efficiency COP is COP = 3, the maximum usable power value Pow_aqMAX is 1.5 from 4.5 / 3 = 1.5 (kW). (KW).

  FIG. 15 shows an operation example when the usable power Pow_aq is set. In the figure, a case where the power consumption due to the load in the home A 1a is increased is illustrated. The load power P4 increases at time t6 during the period when the available power Pow_aq is stable.

  When the load power P4 increases, two cases can be selectively employed as a method for determining whether to decrease or maintain the available power Pow_aq.

  One method is a method of checking whether or not power purchase is made after time t6. When power purchase is necessary, the available power Pow_aq is adjusted in the decreasing direction. When surplus power can cover an increase in power consumption due to an increase in load, the current power consumption of the HPU 7, that is, the heating capacity is maintained.

  Another method is a method of limiting the usable power Pow_aq first. For example, in response to an increase in the load power P4, the available power Pow_aq is decreased by a predetermined amount, thereby preventing power purchase. For example, the available power Pow_aq can be reduced by 0.1 (kW).

  Further, as a method of switching between executing the process of reducing the usable power Pow_aq or executing the process of maintaining, it is possible to use determination of whether or not the increase ΔP4 of the load power P4 exceeds a predetermined threshold value. it can. When the increase ΔP4 exceeds a predetermined threshold, the usable power Pow_aq may be decreased by a predetermined amount, and when the increase ΔP4 does not exceed the predetermined threshold, the usable power Pow_aq may be maintained. For example, when the increase ΔP4 exceeds 0.1 kW, the available power Pow_aq is decreased by a predetermined amount. The fluctuation amount of the load power P4 in the predetermined period can be used as the increase ΔP4.

  FIG. 16 shows an operation example when the usable power Pow_aq is set. In the figure, a case where power purchase is entered, that is, a case where power purchase power P1> 0 is shown. At time t7, power purchase is occurring while the HPU 7 is being operated. After time t7, in order to confirm that it is not a temporary fluctuation, it is determined that power purchase continues for a predetermined time. For example, it is determined that P1> 0 occurs continuously for several seconds. When it is determined that the power purchase is continuous, the available power Pow_aq is decreased. In the illustrated example, after the time t7, the usable power Pow_aq is lowered by a predetermined amount, for example, 0.1 kW.

  If power purchase has occurred after a predetermined time Td1 after time t7, the available power Pow_aq is further reduced at time t8. The process of reducing the available power Pow_aq is repeated until no power purchase occurs. Therefore, when power purchase continues to occur, the process of reducing the available power Pow_aq is repeated, and the available power Pow_aq gradually decreases.

  Eventually, even if the available power Pow_aq reaches the minimum available power value Pow_aqMIN, if power purchase continues to occur for a predetermined time Td1, or the available power Pow_aq is adjusted to be lower than the minimum available power value Pow_aqMIN. If it tries to do so, the operation of the HPU 7 is stopped. In the illustrated example, the operation of the HPU 7 is completely stopped at time t9. In the illustrated example, the minimum usable power value Pow_aqMIN is 0.0 kW. Actually, the operation of the HPU 7 is stopped when the available power Pow_aq reaches the minimum available power value Pow_aqMIN, or when the available power Pow_aq reaches the limit power at which the HPU 7 can be operated.

(Comparison of the number of starts and stops)
FIG. 17 shows the operation of the comparative example. In this comparative example, the hot water supply apparatus is operated using surplus power generated by the on-site power generation facility. In the comparative example, surplus power is used with the same power consumption as in the normal operation in which hot water is stored using power in the midnight hours. In normal operation, relatively high power consumption is consumed in order to achieve high heating efficiency. The heating capacity in normal operation is rated, for example, 4.5 kW. In the comparative example, when the power consumption exceeds the surplus power, the operation of the HPU 7 is stopped.

  In this comparative example, every time the power consumption exceeds the surplus power, the operation of the HPU 7 is stopped to avoid power purchase. As a result, the operation of the HPU 7 is frequently started and stopped as shown in the figure. Such repeated start / stop places an excessive thermal and mechanical burden on the equipment constituting the HPU 7.

  FIG. 18 shows the operation according to this embodiment. In this embodiment, the power consumption of the HPU 7 is limited to less than or less than the available power. In other words, the capacity of the heat pump is limited to less than or less than the available power. Usable power is set to be less than surplus power. Thereby, it is not operated exceeding surplus electric power. As a result, even if a relatively small amount of surplus power is used, the surplus power of the on-site power generation facility can be effectively utilized by converting surplus power into hot water energy and storing it while suppressing the number of times of starting and stopping. .

(Effect of embodiment)
As described above, according to this embodiment, the HPU 7 is operated using surplus power. As a result, electric power that cannot be sold can be used, and efficient control can be provided as a whole of the system including the on-site power generation facility and the hot water supply device. Hot water boiled using surplus electric power can cover hot water used for bathing and dishwashing in ordinary households when solar power generation is stopped from evening to night. Usually, the hot water supply apparatus is set so as to boil hot water using inexpensive electric power such as late-night time. However, it is not necessary to boil the amount boiled with surplus power and in the midnight time zone. In addition, hot water is often used in front of midnight hours, such as baths and showers. The hot water boiled by using the on-site power generation facility such as a solar panel in the daytime has a relatively short time until the hot water is used, and therefore, the heat radiation time while the heat is stored in the hot water storage tank 10 is reduced. For this reason, energy saving is realizable as a whole.

(Second Embodiment)
FIG. 19 shows a control process 250 for the HPC 12 to control the refrigeration cycle. This embodiment is a modification based on the preceding embodiment. Steps 151-160 are the same as those described above. The control process 250 further includes steps 261-263.

  In step 261, the power consumption L at the minimum rotation speed N_min is obtained from the minimum rotation speed N_min of the compressor 14. The power consumption L can also be called necessary power. Here, the calculation formula described in the above embodiment can be used. The minimum rotation speed N_min can be determined based on the system requirements of the HPU 7, that is, the configuration. For example, the minimum rotation speed N_min can be set in consideration of the durability of the lubrication system of the compressor 14. In this calculation, the required power is calculated.

  In step 262, the available power Pow_aq and the power consumption L are compared. When the required power L, that is, the power consumption may be less than the available power Pow_aq, the process proceeds to step 158 and the operation of the HPU 7 is continued. If the available power Pow_aq is insufficient with respect to the required power L, the process proceeds to step 263. In step 263, the operation of the HPU 7 is stopped.

  In this embodiment, the control device, that is, the HPC 12 provides means (step 261) for obtaining the required power L from the outside air temperature Tam, the feed water temperature Twi, and the maximum target discharge temperature. Further, the HPC 12 provides means (step 262) for stopping the operation of the compressor 14 when the required power L is larger than the usable power Pow_aq even if the rotation speed of the compressor 14 corresponding to the required power L is the minimum rotation speed.

  In this embodiment, when the required power L is greater than the usable power Pow_aq (L> Pow_aq), the fan motor 18 that blows air to the air-refrigerant heat exchanger 17 of the refrigeration cycle is operated to accurately acquire the outside temperature Tam. Specific means can optionally be provided.

  The increase in the usable power includes means for outputting a signal indicating that the boiling cannot be performed from the HPC 12 to the TKC 11 or the PWC 4 when the required power L is greater than the usable power Pow_aq, and the TKC 11 or TK in response to the signal. This can be realized by adopting a means for increasing the usable power in the PWC4. According to this configuration, it is possible to increase the usable power in the system-side controller (control device) positioned higher than the HPC 12.

(Third embodiment)
FIG. 20 shows a control process 370 for setting usable power and instructing the HPC 12. This embodiment is a modification based on the preceding embodiment. Steps 171 to 180 are the same as the steps described above. The control process 370 further includes step 381.

  If it is determined in step 177 that there is power purchase, that is, if it is determined that P1> 0, the process proceeds to step 381. When excessive boiling is performed for a predetermined time by the HPU 7, it can be determined that hot water has been stored to some extent. In this case, if it is determined in step 177 that there is power purchase, surplus boiling of the HPU 7 is stopped in step 381. Such a process is advantageous when the cost for purchasing electricity in the daytime exceeds the cost reduction effect of hot water storage in the daytime. In such a case, by stopping the operation of the HPU 7 in step 381, boiling is performed using low-cost electric power such as at midnight. That is, the process proceeds to step 381 when other advantageous power use is possible than the operation of the HPU 7 by power purchase.

  In this embodiment, when the HPC 12 detects that there is purchased power, the HPU 7 stops the operation of the HPU 7, that is, heating by the refrigeration cycle, even if there is surplus power.

(Fourth embodiment)
FIG. 21 shows a control process 470 for setting usable power and instructing the HPC 12. This embodiment is a modification based on the preceding embodiment. The control process 470 employs steps 471 to 473 instead of steps 171 to 173, respectively. Further, steps corresponding to steps 176 to 178 are not adopted.

  This embodiment enables an inexpensive system configuration when the output voltage Vho of the transformer 2b of the system 2 is known. As described above, this embodiment assumes a case where the output voltage Vho of the transformer 2b is known, and there is a consumer having facilities capable of reverse power flow such as solar power generation, for example, B house 1b. ing. In such a case, if the power generation voltage V3 is known in the PWC 4, an inexpensive system configuration in which no extra power sensor is attached as equipment can be adopted.

  In step 471, the voltage V3 is input from the sensor. The voltage V3 is a generated voltage, which is a voltage after being controlled by the PWC 4, that is, after being converted.

  In step 472, the output voltage Vho of the transformer 2b is input. The output voltage Vho is set in the A house 1a via the PWC 4 or the remote controller. The output voltage Vho may be set by an administrator who manages the transformer 2b.

  In step 473, it is determined that the HPU 7 can be operated when all of the following two conditions are satisfied. One condition is that V3 <Vho and the power cannot be sold. Another condition is that the hot water storage tank 10 is in a state where it can be further heated.

  By adopting V3 <Vho as one of the factors for determining whether or not surplus boiling is possible as in this embodiment, priority is given to power sales, even if power that cannot be sold even if the system voltage Vb is lower than B home 1b, The HPU 7 is operated as surplus power, and the HPU 7 is operated with minimum power and low capacity. By using surplus power that cannot be sold in the cloudy or in the morning or evening for heat storage by the HPU 7, surplus power can be effectively utilized without an expensive power sensor. According to this configuration, if V3> Vho, the power can be sold at any time. This makes it possible to sell power immediately even when suddenly using power at B home 1b.

  In this embodiment, the hot water supply system 1 includes a voltage sensor that detects a power generation voltage V3 generated by the premises power generation device 3. Furthermore, the hot water supply system 1, particularly the HPC 12, includes means (step 472) for setting the output voltage Vho of the nearest transformer 2 b in the system 2. The HPC 12 operates the HPU 7, that is, the refrigeration cycle when the generated voltage V3 is lower than the output voltage Vho. This embodiment does not include a power sensor P1 for detecting purchased power and sold power. Further, this embodiment does not include a voltage sensor that detects the system voltage Vb. For this reason, the hot water supply system 1 can be configured at low cost.

(Fifth embodiment)
FIG. 22 shows a control process 570 for setting usable power and instructing the HPC 12. This embodiment is a modification based on the preceding embodiment. The control process 570 employs steps 571-573, 577, and 581 instead of steps 171 to 173, 177, and 181, respectively.

  This embodiment enables an inexpensive system configuration when the output voltage Vho of the transformer 2b of the system 2 is known. In this embodiment, as described above, it is assumed that the output voltage Vho is known and there is a consumer having facilities capable of reverse power flow such as solar power generation, for example, B house 1b. In such a case, if the power generation voltage V3 is known in the PWC 4, an inexpensive system configuration in which no extra power sensor is attached as equipment can be adopted.

  In step 571, the voltage V3 is input from the sensor. The voltage V3 is a generated voltage, which is a voltage after being controlled by the PWC 4, that is, after being converted. Here, a power purchase determination input FBuON is input. The power purchase determination signal FBuON is provided in the A home 1a and is provided from a switch-like circuit that indicates whether there is power purchase by an ON state or an OFF state.

  FIG. 23 shows an example of a power purchase switch circuit 541 that outputs a power purchase determination signal FBuON. The electric power supplied from the system 2 to the PWC 4, that is, the in-home equipment of the home A 1 a is detected by a current sensor 542 including a coil L that detects the current Ip 1. The detection output of the current sensor 542 is supplied to the determination circuit 543. The determination circuit 543 determines whether or not the current Ip1 corresponds to power purchase. The determination circuit 543 includes a reference value circuit including a Zener diode Zd and a resistor, and an operational amplifier AMP. The output of the determination circuit 543 is supplied to an output circuit 544 including transistors Tr1 and Tr2 and a resistor. The output circuit 544 outputs a power purchase determination signal FBuON based on the output of the determination circuit 543. The output circuit 544 outputs an ON state, that is, a voltage Vcc when the current Ip1 flows. The output circuit 544 outputs an OFF state, that is, 0 (V) if the current Ip1 does not flow. Thus, output circuit 544 provides switch actuation.

  As a power sensor, a meter installed by an electric power company to calculate an electricity charge or a power purchase charge by selling power can be used. By using such a meter-type power sensor, it is possible to determine whether or not power is being purchased. However, a configuration for receiving a signal from the meter-type power sensor is required. On the other hand, according to this embodiment, it is possible to determine whether or not there is power purchase with a relatively simple and inexpensive circuit configuration.

  Returning to FIG. 22, in step 572, the output voltage Vho of the transformer 2b is input. The output voltage Vho is set in the A house 1a via the PWC 4 or the remote controller. The output voltage Vho may be set by an administrator who manages the transformer 2b.

  In step 573, it is determined that the HPU 7 can be operated when all of the following three conditions are satisfied. One condition is that V3 <Vho and the power cannot be sold. Another condition is that there is no power purchase instruction input FBuON, that is, FBuON = OFF. Yet another condition is that the hot water storage tank 10 is in a state where it can be further heated.

  In step 577, whether or not there is power purchase is determined based on power purchase determination signal FBuON. If there is power purchase, that is, if FBuON = ON, the process proceeds to step 581. In step 581, the excessive boiling of the HPU 7 is stopped.

  In this embodiment, a step 577 for determining power purchase is added to the control process 470. Thereby, it is determined that there is no surplus power during power purchase, and the operation of the HPU 7 is stopped. If it can be determined that there is no power purchase, the available power Php is increased in step 178. Thereby, the amount of electricity purchased can be reduced as much as possible. Further, by adopting a switch that indicates whether or not power purchase is being performed by an ON or OFF state without providing expensive equipment such as a power sensor, it is possible to adopt a configuration that is relatively cheaper than the power sensor.

  In this embodiment, the hot water supply system 1 includes a power purchase switch circuit 541 that outputs a power purchase determination signal FBuyON indicating power purchase when power purchase from the system 2 is detected. The HPC 12 stops heating by the refrigeration cycle in response to the power purchase determination signal. A switch-type determination circuit 541 that determines power purchase based on a certain threshold instead of the power purchase power P <b> 1 and indicates whether or not power is purchased is indicated by ON (power purchase) or OFF (supply stop or during power sale) is employed. When it is determined that electricity is being purchased based on the output of the switch-like determination circuit 541, the apparatus for boiling water is stopped.

(Sixth embodiment)
FIG. 24 shows an operation example when the usable power Pow_aq is set. This embodiment is a modification based on the preceding embodiment. As shown in the figure, the power generation voltage V3 is increased by the PWC 4 from time t1. In the illustrated example, the maximum value 222 (V) = 202 ± 20 (V) of the standard voltage defined by the Electricity Business Act in Japan is set as the voltage suppression value Vlimit. In the illustrated example, the generated voltage V3 is raised to the voltage suppression value Vlimit.

  Furthermore, in this embodiment, the threshold voltage Vth is employed to determine that the voltage boost for power sale is continuously at a relatively high level. The threshold voltage Vth is also a threshold for determining the frequency at which the boost for power sales reaches a level close to the voltage suppression value Vlimit. The threshold voltage Vth is set lower than the voltage suppression value Vlimit but higher than the standard voltage of the system 2. The threshold voltage Vth can be set to about 60% of the allowable width of the standard voltage. In the illustrated example, the threshold voltage Vth is set to 214 (V) = 202 ± 20 × 0.6.

  In this embodiment, when the generated voltage V3 continues to exceed the threshold voltage Vth during the predetermined time td2, it is necessary to boost the voltage to a high voltage for power sale due to competition with the neighborhood. Is determined. In other words, it is determined that it is difficult to sell power, and it is more efficient to use surplus power on the premises than to boost the voltage for power sale.

  In the illustrated example, the generated voltage V3 continuously exceeds the threshold voltage Vth over a predetermined period td2 between time t2 and time t3. Therefore, at time t3, a surplus determination indicating the generation of surplus power is made. In response to this, at time t3, the usable power Pow_aq is set, and the operation of the HPU 7 is started.

  Further, in the illustrated example, the generated voltage V3 continuously exceeds the threshold voltage Vth over a predetermined period Td2 between time t4 and time t5. Therefore, at time t5, an increase determination is made for an increase in usable power corresponding to the generation of surplus power. In response to this, the available power Pow_aq is set to increase at time t5.

  In the illustrated example, the power generation voltage V3 rapidly decreases at time t6. The generated voltage V3 is lower than the lower limit voltage VL indicating the generation of surplus power at time t6. The lower limit voltage VL is set between the threshold voltage Vth and the standard voltage. In the figure, 208 (V) is illustrated as the lower limit voltage VL. After time t6, V3 <VL continues for a predetermined time td3. In this case, at time t7, a determination is made to return the available power Pow_aq to decrease. In response to this, the available power Pow_aq is decreased by a predetermined amount at time t7.

  When the decrease in the usable power Pow_aq is repeated and the usable power Pow_aq falls below the minimum usable power value Pow_aqMIN, the operation of the HPU 7 is stopped. In the illustrated example, the operation of the HPU 7 is stopped at time t8. Furthermore, when the power generation voltage V3 is boosted again after that, power sales may be started. In the illustrated example, after the time t8, for example, 0.3 kW of power sale is started.

  This embodiment is also configured to use existing equipment without adding an additional power sensor or the like as much as possible. For this reason, generation | occurrence | production of surplus electric power is determined based on the generated voltage V3. In this embodiment, when the voltage suppression at the PWC 4 often works, that is, when the generated voltage V3 is close to the voltage suppression value Vlimit (V3≈Vlimit), surplus power is actively utilized by operating the HPU 7. Judgment whether or not voltage suppression often works is that if the frequency of voltage suppression exceeds a predetermined ratio during the second predetermined time, it is estimated that power competition with neighboring customers has occurred Then, the HPU 7 is operated. The second predetermined time can be about 10 minutes, for example. The predetermined ratio can be about 60%, for example.

  The available power amount Php (Pow_aq) instructed to the HPU 7 is gradually increased. The comparison between the generated voltage V3 and the voltage suppression value Vlimit is performed as needed. When the voltage suppression is removed and the third predetermined time elapses, the usable power Php is gradually decreased. The third predetermined time can be, for example, one hour. Even if the usable power Php is lowered to the minimum usable power value Php_min (Pow_aqMIN), if the voltage suppression is still out, it is determined that the power can be sold, the operation of the HPU 7 is stopped, and the power sale is prioritized. As a result, power sale is carried out after time t8.

  In this embodiment, the HPC 12 that provides the control device operates the refrigeration cycle when it is determined that the time of voltage suppression that suppresses boosting for selling power from the premises power generation device 3 is high at a predetermined frequency. To do. The time and frequency of voltage suppression can be acquired by the PWC 4 that is the control device of the premises power generation device 3, and the frequency can be determined. The HPC 12 can sell power if the usable power Pow_aq indicating the power that can be used by the compressor is the minimum value Php_min (Pow_aqMIN) and the voltage suppression is removed, that is, if the voltage suppression is not executed. The heating by the refrigeration cycle is stopped.

(Seventh embodiment)
This embodiment is a modification based on the preceding embodiment. In this embodiment, the target compressor speed is set according to the characteristics set in the map without employing a complicated theoretical calculation as in the preceding embodiment. Complex theoretical calculations need not be performed in the HPC 12. A map for determining the target compressor speed N from the outside air temperature Tam, the target boiling temperature Tp, and the usable power Pow_aq is obtained in advance at the design stage by calculation. This map is recorded in a storage device such as a semiconductor memory of the HPC 12. According to this configuration, the HPC 12 can determine the target compressor rotation speed (rpm) by searching a map stored in the storage device based on a signal input from a sensor or the like.

  FIG. 25 shows the control characteristics of the comparative example. In the comparative example, the heat pump unit is controlled so as to boil the hot water in the hot water storage tank by the target time even if the heating capacity and the heating load change depending on the outside air temperature Tam and the feed water temperature Twi. This configuration provides the advantage that the required heating capacity can be realized with high efficiency. As shown in the figure, in the comparative example, the rotational speed of the compressor is determined based on the outside air temperature, and is correlated with the target heating capacity.

  FIG. 26 illustrates the operation according to this embodiment. In this embodiment, surplus power is generated when power cannot be sold, for example, the amount of power generated from the on-site power generation facility exceeds the amount that can be sold in the daytime. In this embodiment, a small amount of hot water is boiled with low power by using surplus power. As a result, the surplus power can be converted into hot water energy and used effectively without being discarded. In this embodiment, the rotation speed of the compressor 14 is adjusted according to the available power set according to the state of the power system. The rotation speed of the compressor 14 is determined by the target boiling temperature and the outside air temperature.

  In this embodiment, the HPC 12 that provides the control device includes a storage device that stores a map for determining the target rotational speed based on the outside air temperature Tam and the target boiling temperature Tp. The HPC 12 provides a means for determining the target rotational speed based on the map. The map is set so that the target rotational speed is determined from the available electric energy based on environmental conditions such as the outside air temperature Tam and the target boiling temperature Tp.

(Eighth embodiment)
This embodiment is a modification based on the preceding embodiment. This embodiment performs cooperation with the entrusted control on the hot water storage tank side as compared with the amount of late-night boiling. In this embodiment, the HPC 12 includes a totaling unit that aggregates the amount of heat pump boiling water, that is, the amount of stored heat, so as to be understood as an average Qavr for the past week. The HPC 12 should calculate the amount of surplus heat storage that can be stored in excess from the accumulated power that can be used as surplus power during the day, and perform heat storage using surplus power compared to the amount of midnight heat storage that can be stored during midnight hours. In some cases, boiling with surplus power is performed.

  For example, the following assumptions can be made. Assuming that Qavr = 9.0 (kW · h), electricity sales fee is 48 (yen / kW · h), daytime electricity purchase fee is 30 (yen / kW · h), and midnight electricity purchase fee is 10 ( Yen / kW · h). In order to simplify the calculation, the HPU 7 has a characteristic that ignores the loss and is uniform, with COP = 4 and heating capacity Q = 4.5 (kW · h (midnight)). Note that these unit prices are provisional values for calculation.

  When hot water is boiled in the hot water storage tank 10 only at midnight, 2 (h) (= Qavr / Q), electric power L = Q / COP = 1.125 (kW), electricity rate = 10 (yen) × 1. 125 × 2 = 22.5 (yen).

  If surplus power that cannot be sold in the daytime is covered, the surplus heating capacity Qy = 0.5 × COP (= 4) = 2 (kW) when the usable power amount is 0.5 (kW). In terms of time, Qavr / Qy = 4.5 (h: time) is required.

  In the daytime when sunlight can be obtained, for example, when surplus power is obtained during the period from 10:00 to 16:00 and the HPU 7 can be operated by the surplus power, the amount of heat stored in the midnight time zone can be increased by the surplus power during the daytime. You can store hot water with the equivalent amount of heat. The amount of electric power is 0.5 × 4.5 = 2.25 (kW · h). When this amount of power is purchased, 30 (yen) × 2.25 = 26.7 (yen).

  If only about half the amount of hot water that needs to be stored in the hot water storage tank 10 during the day can be boiled, the amount of power is 0.5 × 2.25 = 1.125 (kW · h), In terms of quantity, Qhd = COP × 1.125 = 4.5 (kW · h). Since the remaining amount of hot water is Qavr-Qhd, it is 4.5 (kW · h). The electricity bill for midnight will be 11.25 yen. When the daytime power can be sold, 48 (yen) × 1.125 = 54 (yen). Compared to the time when everything is stored in the middle of the night, the calculation is about 42 (yen) (= 54-11.25). However, if you cannot sell electricity at all, you can get 11.25 (yen) by driving the HPU 7 in surplus. In addition, although HPU7 is drive | operated as a surplus, there exists a possibility that electric power purchase may generate | occur | produce.

  In this embodiment, the actual heating capacity is calculated when boiling with surplus electric power in the daytime, and the HPU 7 that is in an efficient use range without excessive heat storage by reducing the amount of boiling at night is correspondingly reduced. Can be executed. In this embodiment, the HPC 12 that provides the control device calculates the actual heating capacity amount boiled by the surplus power in the daytime of the on-site power generation device 3, and by the amount of the actual heating capacity amount, in the midnight time zone when the power rate is low Decrease boiling time in midnight hours by reducing boiling time.

(Other embodiments)
The preferred embodiments of the disclosed invention have been described above, but the disclosed inventions are not limited to the above-described embodiments, and various modifications can be made. The structure of the said embodiment is an illustration to the last, Comprising: The technical scope of several disclosed invention is not limited to the range of these description. The disclosed inventions are not limited to the combinations shown in the embodiments, and can be implemented independently. Some technical scopes of the disclosed inventions are indicated by the description of the claims, and include all modifications within the meaning and scope equivalent to the description of the claims.

  For example, the means and functions provided by the control device can be provided by software only, hardware only, or a combination thereof. For example, the control device may be configured by an analog circuit.

  In the above-described embodiment, the available power Pow_aq is instructed from the tank or the PWC 4 or the TKC 11, that is, from the system-side controller to the HPC 12 on the HPU 7 side. In the control processes 150 and 250, the control target device of the HPU 7 is controlled based on the available power Pow_aq.

  Instead, the HPC 12 may set the target power consumption Ltg to control the control target device of the HPU 7. For example, in the HPC 12, the target power consumption Ltg can be set with a margin for the available power Pow_aq.

  For example, the target power consumption Ltg can be obtained from Ltg = Pow_aq−AL based on the margin amount AL. The control processes 150 and 250 are executed using the target power consumption Ltg instead of the available power Pow_aq. The allowance AL is set in order to allow a sufficient control by the accuracy of the detection signal IDC of the current sensor built in the inverter 13 and the conversion accuracy of the DC voltage. The DC voltage is converted from a high voltage such as 300V to a 5V system in order to use A / D conversion, that is, DC-DC conversion.

  In this modification, the HPC 12 obtains the target power consumption Ltg having a margin for the available power, and obtains the target rotational speed Ntg from the target power consumption at the start of operation, so that the rotational speed of the compressor 14 becomes the target rotational speed. The 1st control part (step 158) which controls to become is provided. Further, the HPC 21 provides a second control unit (step 160) that feedback-controls the rotation speed of the compressor 14 so that the power consumption of the compressor 14 becomes the target power consumption after a predetermined time of operation from the start of operation.

1 Hot water supply system, 1a A house (customer), 1b B house (customer),
2 systems, 2a substation, 2b transformer,
3 On-site power generator (solar panel),
4 Power conditioner (PWC),
5 Water heaters,
6 Tank unit (TKU), 7 Heat pump unit (HPU),
10 hot water storage tank, 11 tank controller (TKC),
12 Heat pump controller (HPC),
13 Inverter, 14 Compressor.

Claims (16)

A hot water storage tank (10),
Refrigeration having a water-refrigerant heat exchanger (15) for heating the water supplied to the hot water storage tank and an electric compressor (14) for compressing the refrigerant supplied to the water / refrigerant heat exchanger and capable of operating a heat pump Cycle,
As the heat source of the refrigeration cycle, usable power (Pow_aq, Php) that is set based on surplus power that is generated by the on-premises power generator (3) and cannot be sold to the grid (2) and that indicates the power that can be used by the compressor A control device (12) for determining a target discharge temperature (Tb) and a target rotation speed of the compressor (14) based on an outside air temperature (Tam) which is a temperature of outside air, and controlling the compressor (14). Hot water supply device characterized by The control device (12)
A target power consumption (Ltg) having a margin with respect to the usable power is obtained, and at the start of operation, a target rotational speed (Ntg) is obtained from the target power consumption, and the rotational speed of the compressor becomes the target rotational speed. A first control unit (158) for controlling
The second control unit (160) that feedback-controls the rotation speed of the compressor so that the power consumption of the compressor becomes the target power consumption when the operation is performed for a predetermined time from the start of operation. Water heater. The control device includes:
Means (154) for estimating the refrigerant enthalpy (ib) at the outlet of the compressor from the target boiling temperature (Tp);
Means (155) for estimating the enthalpy (ia) of the refrigerant in the suction of the compressor from the outside air temperature;
The hot water supply apparatus according to claim 1 or 2, further comprising means (158) for determining the target discharge temperature and the target rotational speed based on a plurality of the enthalpies. The control device includes:
Means (261) for determining required power (L) from the outside air temperature and the water supply temperature;
A means (262) for stopping the operation of the compressor when the required power is larger than the usable power even if the rotation speed of the compressor corresponding to the required power is the lowest. The hot water supply device according to any one of claims 1 to 3.   When the required electric power is larger than the usable electric power (L> Pow_aq), a means for operating the fan motor that blows air to the air refrigerant heat exchanger of the refrigeration cycle to accurately acquire the outside air temperature is provided. Item 5. A water heater according to item 4.   The hot water supply apparatus according to claim 4 or 5, further comprising means for increasing the usable power when the required power is larger than the usable power (L> Pow_aq).   The hot water supply apparatus according to any one of claims 1 to 6, wherein the target discharge temperature is set as a value obtained by adding a predetermined value to the target boiling temperature (Tp).   The control device (12) includes a storage device that stores a map for determining the target rotational speed based on the outside air temperature and the target boiling temperature (Tp), and determines the target rotational speed based on the map. The hot water supply device according to any one of claims 1 to 7, wherein   The control device calculates the actual heating capacity amount boiled by surplus electric power in the daytime of the on-site power generation device (3), and the amount of time for boiling in the midnight time zone when the power rate is cheaper by the amount of the actual heating capacity amount. The hot water supply device according to any one of claims 1 to 8, wherein the boiling time in the midnight time zone is reduced by reducing the time. On-site power generation device (3),
A power sensor for detecting the purchased power (P1) purchased from the system (2) and the sold power (P2) for selling the generated power generated by the on-premises power generator to the system;
A voltage sensor that detects the voltage (Vb) of the purchased power as a system voltage of the system (2);
A hot water storage tank (10),
Refrigeration having a water-refrigerant heat exchanger (15) for heating the water supplied to the hot water storage tank and an electric compressor (14) for compressing the refrigerant supplied to the water / refrigerant heat exchanger and capable of operating a heat pump Cycle,
When the system voltage (Vb) is higher than the upper limit (Vlimit) of the power generation voltage (V3) of the on-site power generation device, the on-site power generation device determines that surplus power can be generated, and the surplus power generates the refrigeration cycle. A hot water supply system comprising a control device (12) for operation.   The control device is set based on surplus power that is generated by the on-site power generation device (3) and cannot be sold to the grid (2), and usable power (Pow_aq, Php) indicating power that can be used by the compressor, and Determining a target discharge temperature (Tb) and a target rotational speed of the compressor (14) based on an outside air temperature (Tam) which is an outside air temperature as a heat source of the refrigeration cycle, and controlling the compressor (14). The hot water supply system according to claim 10, wherein   The hot water supply system according to claim 10 or 11, wherein when the control device detects that the purchased power is present, heating by the refrigeration cycle is stopped even if surplus power is present. Furthermore, a voltage sensor for detecting a power generation voltage (V3) by the on-site power generation device (3),
Means (472) for setting the output voltage (Vho) of the nearest transformer (2b) in the system (2),
The hot water supply system according to any one of claims 10 to 12, wherein the control device operates the refrigeration cycle when the generated voltage is lower than the output voltage. Furthermore, it comprises a power purchase switch circuit (541) that outputs a power purchase determination signal (FBuON) indicating power purchase when power purchase from the system is detected,
The hot water supply system according to any one of claims 10 to 13, wherein the control device stops heating by the refrigeration cycle in response to the power purchase determination signal. The control device includes:
When it is determined that the time of voltage suppression that suppresses boosting for selling power from the premises power generation device (3) is high at a frequency during a predetermined time, the refrigeration cycle is operated,
If the available power (Pow_aq, Php) indicating the power that can be used by the compressor is the lowest value and the voltage suppression is removed, it is determined that the power can be sold, and heating by the refrigeration cycle is stopped. The hot water supply system according to any one of claims 10 to 14, wherein:   The control device calculates the actual heating capacity amount boiled by surplus electric power in the daytime of the on-site power generation device (3), and the amount of time for boiling in the midnight time zone when the power rate is cheaper by the amount of the actual heating capacity amount. The hot water supply system according to any one of claims 10 to 15, wherein the boiling time in the midnight time zone is reduced by reducing the time.

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