JP2010243111A - Heat pump type water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To ensure a target heat storage amount in a midnight power time zone by improving an operation time average COP (Coefficient Of Performance) in a boiling-up operation to store the heated hot water in a tank. <P>SOLUTION: This heat pump type water heater includes a refrigerant circuit, a hot water supply circuit for storing the water heated by a water-refrigerant heat exchanger in the tank, a target heat storage amount calculating means for calculating the target heat storage amount to store hot water in the tank, an in-tank heat storage amount detecting means for detecting a heat storage amount stored in the tank, a heating capacity calculating means for calculating a heating capacity of the boiling-up operation, and an operation control means for controlling the boiling-up operation to the tank. The heating capacity calculated by the heating capacity calculating means, is obtained by multiplying a heating capacity obtained by dividing a heat quantity as a result of subtraction of the in-tank heat storage amount detected by the in-tank heat storage amount detecting means from the target heat storage amount calculated by the target heat storage amount calculating means, by a time from a start time to a termination time of the midnight power time zone, by a prescribed constant or adding the prescribed constant to the heating capacity, and the boiling-up operation is started at the start time of the midnight power time zone. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a heat pump type hot water heater, and more particularly, to a heat pump type hot water heater that improves an operating time average COP (energy consumption efficiency) during a boiling operation in which heated hot water is stored in a tank.

  In the heat pump type hot water heater, the operation of the heat pump type hot water heater is started when the hot water (amount of remaining hot water) stored in the tank is reduced, and the operation is stopped when a predetermined amount of hot water is secured.

  A conventional heat pump type hot water heater detects the amount of remaining hot water in a tank, calculates a necessary amount of heat, and operates at a compressor frequency that maximizes the COP of the heat pump type hot water heater based on the amount of heat (for example, patents) Reference 1).

JP-A-9-68369

  Heat pump water heaters require several tens of minutes from the start of operation until the state of the refrigerant in the refrigeration cycle stabilizes, and transient COP and heating capacity are compared to stable COP and heating capacity. It is characterized by being low. Here, COP is energy consumption efficiency, and is the ratio of the heating capacity to the input supplied to the heat pump type hot water heater.

  Therefore, the shorter the time from the start of operation of the heat pump hot water heater to the stop, the COP or heating capacity of the refrigerant in the refrigeration cycle is stable with respect to the total operation time of the heat pump hot water heater. The proportion of operating time with low COP and low heating capacity increases. Therefore, the average COP and the average heating capacity of the operation time of the heat pump type hot water heater are lowered.

  When the conventional heat pump type water heater described in Patent Document 1 is operated without changing the compressor frequency from the start time to the end time of the midnight power time period in order to improve the average COP of the operation time, Since the heating capacity immediately after the start of operation, which is lower than that in the stable state, is not taken into consideration, the necessary amount of heat cannot be secured in the midnight time zone.

  The present invention has been made to solve the above-described problems, and can improve the average operating time COP during a boiling operation in which hot water heated by a heat pump type hot water heater is stored in a tank, and is within a midnight power time zone. An object is to provide a heat pump type water heater that can secure the necessary amount of hot water storage.

The heat pump type hot water heater according to the present invention includes a refrigerant circuit in which a compressor, a water refrigerant heat exchanger, an expansion valve, and an air heat exchanger are annularly connected, and water heated by the water refrigerant heat exchanger in the tank. Hot water supply circuit for storing hot water, target heat storage amount calculation means for calculating the target heat storage amount stored in the tank, heat storage amount detection means for detecting the heat storage amount in the tank, heating capacity calculation for calculating the heating capacity of the heating operation Means, and operation control means for controlling the heating operation to the tank,
The heating capacity calculated by the heating capacity calculation means is calculated by subtracting the amount of heat stored in the tank detected by the tank heat storage amount detection means from the target heat storage amount calculated by the target heat storage amount calculation means. The heating capacity divided by the time from the start time to the end time is multiplied by or added to a predetermined constant, and the operation control means for controlling the heating operation is performed at the start time of the midnight power time zone. The lift operation is started.

  According to the heat pump type water heater according to the present invention, during the boiling operation, by operating from the start time to the end time of the midnight power time zone, the COP immediately after the start of operation with respect to the total operation time of the boiling operation is low. The operation time ratio can be reduced, the operation time average COP can be improved, and the necessary amount of heat can be reliably ensured within the midnight power hours.

1 is a system circuit diagram of a heat pump type water heater according to an embodiment of the present invention. It is a diagram which shows the time change of COP and a heating capability from the operation start of the heat pump type water heater of FIG. It is a flowchart figure which shows the boiling operation method of the heat pump type hot water heater of FIG.

Embodiment.
In FIG. 1 according to an embodiment of the present invention, a heat pump type hot water heater includes a heat pump unit 100 and a tank unit 200. In the heat pump unit 100, a compressor 1, a water refrigerant heat exchanger 2, an expansion valve 3 and an air heat exchanger 4 are sequentially connected in an annular manner, and a refrigeration cycle (refrigerant circuit) 101 in which refrigerant circulates, and air heat exchange. A fan 5 for blowing outside air is mounted on the vessel 4. On the other hand, in the tank unit 200, a pump 6 that supplies water as a load-side medium to the water-refrigerant heat exchanger 2, and a tank that stores water that is supplied by the pump 6 and heated by the water-refrigerant heat exchanger 2. 7 is installed. And the hot water supply water circuit (hot water supply circuit) 201 is comprised by connecting the water-refrigerant heat exchanger 2, the tank 7, and the pump 6 by connection piping 8a-8f. The pump 6 is not necessarily installed in the tank unit 200, and may be mounted on the heat pump unit 100 side.

  In FIG. 1, a hot water supply apparatus that supplies hot water having a constant temperature stored in the tank 7 of the hot water supply circuit 201 to, for example, a bath is omitted. A circuit for supplying water from the hot water supply circuit 201 is also omitted. In addition, the compressor drive device (not shown) uses an inverter-controlled DC brushless motor so that the rotation speed is variable so that the pressure and temperature of the refrigerant discharged from the compressor 1 can be changed. However, a plurality of compressors 1 may be combined, and this combination may be switched to make the overall capacity variable. In addition, a structure such as a suction muffler that reduces refrigerant noise on the suction side of the compressor 1 or a device that collects lubricating oil that has flowed out to the discharge side of the compressor 1 may be added. . As a refrigerant of this heat pump type hot water heater, a refrigerant capable of producing high temperature hot water, for example, a refrigerant such as carbon dioxide, R410A, propane or propylene is suitable, but is not particularly limited thereto.

  In the heat pump unit 100, in the hot water supply circuit 201, the incoming water temperature sensor 9 a is provided on the water inlet side of the water refrigerant heat exchanger 2, and the outgoing hot water temperature sensor 9 b is provided on the water outlet side of the water refrigerant heat exchanger 2. Measure the water temperature at each location. The outside air temperature sensor 9 c provided at or near the outer periphery of the heat pump unit 100 measures the outside air temperature around the heat pump unit 100. In the refrigeration cycle 101, the discharge temperature sensor 9 d is provided on the outlet side of the compressor 1, the suction temperature sensor 9 e is provided on the inlet side of the compressor 1, and the evaporation temperature sensor 9 f is provided on the intermediate portion from the inlet of the evaporator 4. The temperature of the refrigerant at each location is measured. Moreover, hot water storage temperature sensors 9g to 9j are provided on the surface of the tank 7 in the tank unit 200, and measure the water temperature in the tank.

  In the heat pump unit 100, a measurement control device 10 as a control means is provided. This measurement control device 10 is based on the measurement information obtained by the temperature sensors 9a to 9g and the content of operation command information instructed by a remote control device or the like from the user of the heat pump hot water heater. The opening degree of the expansion valve 3, the operation method of the pump 6, the boiling operation described later, and the like are controlled.

Next, the operation | movement operation | movement in this heat pump type water heater is demonstrated. Here, the boiling operation will be described.
In the boiling operation, the refrigeration cycle 101 and the hot water supply circuit 201 are operated, low temperature water is discharged from the water intake port 7b at the bottom of the tank 7 by the pump 6, and is sent to the water refrigerant heat exchanger 2, where water refrigerant heat The heat exchanger boils up by exchanging heat with the refrigerant in the exchanger 2 and returns to the tank 7 from the hot water storage port 7 a at the top of the tank 7.

  In the refrigeration cycle 101 of the heat pump unit 100, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 decreases in temperature while radiating heat (heats water) to the hot water supply circuit 201 side in the water refrigerant heat exchanger 2. At this time, if the high-pressure side refrigerant pressure is equal to or higher than the critical pressure, the refrigerant radiates heat at a reduced temperature without undergoing a gas-liquid phase transition in a supercritical state. If the high-pressure side refrigerant pressure is equal to or lower than the critical pressure, the refrigerant radiates heat while liquefying. That is, hot water supply heating (boiling) is performed by applying heat radiated from the refrigerant to a load-side medium (here, water flowing through the hot water supply water circuit 201). The high-pressure and low-temperature refrigerant flowing out of the water-refrigerant heat exchanger 2 through hot water heating passes through the expansion valve 3.

  The refrigerant that has passed through the expansion valve 3 is reduced in pressure to a low-pressure gas-liquid two-phase state. The refrigerant that has passed through the expansion valve 3 flows into the air heat exchanger 4 where it absorbs heat from the outside air and is evaporated and gasified. The low-pressure refrigerant that has exited the air heat exchanger 4 is sucked into the compressor 1 and circulated to form a refrigeration cycle 101.

  On the hot water supply circuit 201 side, the water in the tank 7 is guided by the pump 6 from the water intake 7b at the bottom of the tank 7, passes through the connection pipes 8d to 8f, and is conveyed into the water / refrigerant heat exchanger 2. The Then, it is heated (boiling) by exchanging heat with the refrigerant, passes through the connecting pipes 8 a to 8 c, and flows into the tank 7 from the hot water storage port 7 a at the upper part of the tank 7. As a result, the inside of the tank 7 is in a state of high temperature water at the top and low temperature water at the bottom.

Next, the operation control operation in this heat pump type hot water heater will be described.
First, the operating capacity of the compressor 1 and the rotational speed of the pump 6 controlled by the rotational speed and the like are adjusted based on the heating capacity calculated by the measurement control device 10 described later. In other words, the temperature of the water at the water outlet of the water-refrigerant heat exchanger 2 (the temperature of the hot water), which is measured and detected by the heating capacity and the temperature of the hot water temperature sensor 9b, is adjusted and controlled so as to become a predetermined target value. The target hot water temperature is set from the operation command information instructed by the remote controller from the user, or the heat storage energy calculated from the past hot water use amount in the remote controller or by the microcomputer provided in the measurement control device 10 It is set so that (hot water storage) can be secured. Further, the target hot water temperature has a predetermined range, for example, a range of 65 ° C. to 90 ° C.

  If the predetermined heating capacity can be ensured with the maximum value in the target hot water temperature range, the predetermined heating capacity can be secured within the target hot water temperature range. Therefore, the rotation speed of the compressor 1, which is the heating capacity of the water-refrigerant heat exchanger 2, is adjusted based on, for example, the outside air temperature and the feed water temperature as described above, so that a predetermined heating can be achieved at any target tapping temperature. Capability can be secured. In other words, the output of the compressor 1 is provided with a heating capacity that can ensure the temperature of hot water required as a water heater for any external conditions at any time. Can be obtained as a water heater. Moreover, the rotation speed of the compressor 1 is provided with an upper limit rotation speed and a lower limit rotation speed from the viewpoint of compressor durability.

  The opening degree of the expansion valve 3 is controlled so that the discharge temperature becomes a predetermined value (target discharge temperature). The target discharge temperature is set to a temperature higher than the target hot water temperature, that is, the target hot water temperature + α [° C.] in order to make the target hot water temperature secureable. The value α is, for example, a function of the outside air temperature or the target hot water temperature. Thus, the required hot water temperature can be ensured by setting it as the target discharge temperature according to the target hot water temperature. Also, from the viewpoint of compressor durability and refrigeration machine oil degradation, an upper limit temperature is usually provided for the discharge temperature.

  The rotation speed of the pump 6 is controlled so that the tapping temperature becomes the target tapping temperature. Since the discharge temperature is controlled to the target hot water temperature + α [° C.] by the expansion valve 3, that is, the heating capacity on the refrigeration cycle 101 side is kept constant, the hot water temperature can be reliably ensured.

  Next, an operation method of the heat pump unit 100 which is a characteristic part of the heat pump type hot water heater of the present embodiment will be described.

FIG. 2 shows changes in the COP and the heating capacity q with respect to the elapsed time from the start of operation of the heat pump unit 100. As shown in FIG. 2, the COP and the heating capacity q of the heat pump unit 100 approach a constant value and become stable after several tens of minutes from the start of operation.
As shown in FIG. 2, the time required for the COP and the heating capacity q to stabilize is that immediately after the operation of the heat pump unit 100 is started, water as a load medium is heated, and at the same time, the compressor 1 and the water refrigerant This is because the heat exchanger 2 needs to be heated. Before the operation of the heat pump unit 100 is started, the compressor 1 and the water refrigerant heat exchanger 2 are at a temperature equivalent to the outside air temperature. Immediately after the operation of the heat pump unit 100 is started, the high-temperature and high-pressure gas refrigerant needs to heat the water and simultaneously heat the compressor 1 and the water-refrigerant heat exchanger 2. Therefore, immediately after the start of operation, the amount of heat that can heat the load medium water decreases, and the heating capacity q of the heat pump unit 100 decreases. Since the electric input to be input to the heat pump unit 100 is the same immediately after the start of operation and when it is stable, the COP is in an operation state in which the COP is lower immediately after the start of operation than when it is stable.

  In particular, household heat pump hot water heaters often use a high-pressure shell type compressor that discharges the refrigerant compressed in the compressor 1 into the compressor shell, and often uses carbon dioxide as the refrigerant. When the refrigerant is carbon dioxide, the high pressure side in the refrigeration cycle 101 becomes the critical pressure (about 7.4 MPa) or more, so the design pressure increases and the plate thickness (thickness) of the compressor shell increases. Therefore, the heat capacity of the compressor shell is increased, the amount of heat by which the refrigerant heats the compressor 1 is larger than that of other refrigeration equipment, and the time required until the COP and the heating capacity q are stabilized also increases.

  As described above, the time required for the COP and heating capacity immediately after the start of operation to stabilize can be shortened by the operation method of the heat pump unit 100, but cannot be omitted. For this reason, the shorter the boiling operation time of the heat pump unit 100, the larger the ratio of the time required from the start of operation to the boiling operation time until the COP and the heating capacity are stabilized, and the average COP of the boiling operation time, The average heating capacity will decrease.

  Further, when the outside air temperature is low during the operation of the heat pump unit 100 and the temperature of the refrigerant passing through the air heat exchanger 4 becomes 0 ° C. or less, the air heat exchanger 4 is frosted and the heating capacity q decreases. It is necessary to carry out defrosting operation. Similarly, when the operation is resumed after completion of the defrosting operation, the COP and the heating capacity q of the heat pump unit 100 are lower than those at the time of stabilization. This defrosting operation is performed when a predetermined condition is satisfied until the boiling operation ends, for example, when the evaporating temperature sensor 9f detects a predetermined temperature for a predetermined time. Therefore, when it is at the outside air temperature where the defrosting operation is performed, the average COP and the average heating capacity of the heating operation time are lower than when the defrosting operation is not performed.

  Therefore, in the present embodiment, the heating capacity q that can secure a predetermined amount of stored hot water in the tank by operating the heat pump unit 100 from the start time to the end time of the late-night power time period when the electricity rate is cheap from midnight to early morning. The operation of the heat pump unit 100 is started at the start time of the midnight power time zone with the heating capacity q ′ increased by multiplying or adding a predetermined constant.

FIG. 3 is a flowchart showing a boiling operation method of heat pump unit 100 according to the embodiment of the present invention.
First, in step S-1, the measurement control apparatus 10 detects the amount of heat stored in the tank 7 detected by the in-tank heat storage amount calculating means installed in the tank unit 200, for example, the hot water storage temperature sensors 9g to 9j installed in the tank 7. The amount of heat stored in the tank (Qr) is calculated from the water temperature.

  Next, in step S-2, the measurement control device 10 calculates a target heat storage amount Q. The calculation of the target heat storage amount Q may be the heat storage amount corresponding to the operation mode of the heat pump water heater determined by the user, or from the heat usage for the past several days stored in the storage means in the measurement control device 10. It may be calculated.

After calculating the target heat storage amount Q, in step S-3, the measurement control device 10 calculates the target hot water temperature Ta.
Here, the target hot water temperature Ta is L [L], the target hot water temperature Ta [° C.] detected by the boiling water volume calculating means in the tank 7, the water temperature detected by the incoming water temperature sensor 9a. Is Tb [° C.], the target heat storage amount is Q [kJ], the tank heat storage amount is Qr [kJ], the water specific heat is Cp [kJ / kg · K], and the water density is D [kg / m ³ ]. The following (Equation 1) is satisfied and the hot water temperature is within a predetermined range.
Ta ≧ Tb + (Q−Qr) / (Cp × D × L) (Formula 1)
Here, the boiling water amount calculating means is calculated from, for example, the water temperature in the tank 7 detected by the hot water storage temperature sensors 9g to 9j, or the tank of the past several days stored in the storage means in the measurement control device 10. Calculate from the amount of water used.

Next, in step S-4, the measurement controller 10 uses the following (formula 2) and (formula 3) to heat the heat pump unit 100 and the flow rate Gw [kg / s] of water circulating through the heat pump unit 100. Capability q [kW] is calculated. Here, t [s] is the boiling operation time, which is the time from the current time detected by the measurement control device 10 to the end time of the midnight power period. If the detection time is 10 pm and the end time is 7 am, then 9 hours = 32400 seconds.
Gw = (Q−Qr) / {(Ta−Tb) × Cp × t} (Formula 2)
q = Gw × Cp × (Ta−Tb) = (Q−Qr) / t (Formula 3)
The heating capacity q ′ [kW] of the heat pump unit 100 in consideration of the low heating capacity operation state immediately after the start of operation is a value obtained by multiplying the heating capacity q calculated by (Equation 3) by a predetermined constant C. , (Equation 4).
q ′ = C × q = (C × Gw) × Cp × (Ta−Tb) = Gw × Cp × ((C × Ta) −Tb)) (Formula 4)
In (Expression 4), the predetermined constant C is expressed by multiplying either the target hot water temperature Ta determined in (Expression 1) or the flow rate Gw of water determined in (Expression 2). That is, the heating capacity q ′ obtained by multiplying the heating capacity q by a predetermined constant C is a value obtained by multiplying the target hot water temperature Ta or the flow rate Gw of water by the constant C. Further, the heating capacity q ′ increased by adding a predetermined constant C ′ to the heating capacity q calculated by (Expression 3) is calculated by (Expression 5).
q ′ = C ′ + q = Gw ′ × Cp × (Ta−Tb) = Gw × Cp × (Ta′−Tb)
(Formula 5)
The water flow rate Gw ′ [kg / s] and the target hot water temperature Ta ′ [° C.] in (Expression 5) are calculated by the following (Expression 6) and (Expression 7).
Gw ′ = Gw + C ′ / {(Ta−Tb) × Cp} (Formula 6)
Ta ′ = Ta + C ′ / (Gw × Cp) (Formula 7)
Here, the predetermined constant C shown in (Equation 4) and the predetermined constant C ′ shown in (Equation 5) to (Equation 7) may be constant values, or as functions of the outside air temperature and the heating capacity. good.
After calculating the heating capacity q ′, the measurement controller 10 adjusts the operating frequency of the compressor 1, the opening of the expansion valve 3, the rotational speed of the blower fan 5, and the pump 6 so as to satisfy the calculated heating capacity q ′. Determine the number of revolutions.

Next, in step S-5, the measurement control device 10 determines whether or not the time is in the midnight power time zone using a timer or the like.
When the midnight power time zone is from 11 pm to 7 am, if the detection time is 10 pm, the process returns to step S-1, and if the detection time is 11 pm, the process proceeds to step S-6.

Next, in step S-6, the measurement controller 10 determines that the heating capacity q ′ calculated in step S-4 is the minimum heating capacity qmin when the compressor 1 of the heat pump unit 100 is operated at the lower limit rotation speed. It is judged whether it is above.
When it is determined that the minimum heating capacity is qmin or more, the operation of the heat pump unit 100 is started.

Since the heat pump unit 100 cannot be operated when the heating capacity q ′ is equal to or less than the minimum heating capacity qmin, when the heat pump unit 100 is operated with the minimum heating capacity qmin in step S-7, an operation capable of securing the target heat storage amount Q. Calculate the start time.
In order to calculate the operation start time, first, the operation time tmin at the minimum heating capacity is obtained by the following (Equation 8). Here, the operation time at the minimum heating capacity is tmin [s], and the minimum heating capacity is qmin [kW].
tmin = (Q−Qr) / qmin (Formula 8)
Even when the operation is performed with the minimum heating capacity, immediately after the operation starts, there is a time for heating with a small heating capacity compared with the stable time. Therefore, in order to secure the target heat storage amount, the operation time is obtained by multiplying tmin by a predetermined constant B. Need to be long. Therefore, the operation time tmin ′ [s] at the minimum heating capacity qmin in consideration of the operation state with a low heating capacity immediately after the start of operation is calculated by the following (Equation 9).
tmin ′ = B × tmin = B × (Q−Qr) / qmin (Formula 9)
Further, a predetermined constant B ′ may be added to the operation time tmin ′ [s] at the minimum heating capacity qmin in consideration of an operation state with a low heating capacity immediately after the start of operation. The operation time tmin ′ [s] at this time is calculated by the following (Equation 10).
tmin ′ = B ′ × tmin = B ′ × (Q−Qr) / qmin (Formula 10)
Here, the predetermined constant B shown in (Equation 9) and the predetermined constant B ′ shown in (Equation 10) may be constant values, or may be functions of the outside air temperature and the heating capacity.
When tmin ′ [s] calculated in (Equation 9) or (Equation 10) is 21600 seconds = 6 hours and the end time of the midnight power time zone is 7:00 am, the minimum heating capacity qmin [kW] The operation start time is 1 am.

  After calculating the operation start time at the minimum heating capacity qmin, in step S-8, it is determined whether it is the start time in the minimum heating capacity operation. If it is the start time, the heat pump unit 100 is operated at the minimum heating capacity qmin in step S-9. Start driving.

  After the operation of the heat pump unit 100 is started, in step S-10, the measurement control device 10 determines by a timer or the like whether the time is the end time of the midnight power period every predetermined time, for example, every hour. When it is determined that the end time of the midnight power time zone is reached, the operation of the heat pump unit 100 is stopped, and the boiling operation ends.

  Here, Step S-6 to Step S-8 are effective as means for ensuring the target heat storage amount Q when the heat pump unit 100 has the minimum heating capacity qmin. If there is no rotation speed and there is no minimum heating capacity qmin, this means is not necessary, and the process proceeds from step S-5 to step S-9.

  When the defrosting operation is performed during the operation of the heat pump unit 100, the pump 6 is stopped during the defrosting operation and the heating capacity is not generated. Therefore, the heating capacity q ′ calculated in step S-4 after the defrosting operation is completed. When the operation of the heat pump unit 100 is continued, the necessary hot water storage amount cannot be secured within the midnight power time zone. Therefore, when the defrosting operation is performed, the process returns to step S-1 after the defrosting operation is completed, and the boiling operation is continued with the heating capacity q 'calculated again. Thereby, also when implementing a defrost operation, the amount of hot water storage required can be ensured.

  Further, since the outside air temperature decreases from the start time to the end time of the midnight power time period, the operation frequency of the compressor 1, the opening degree of the expansion valve 3, and the blower fan 5 determined by the measurement control device 10 in step S-4. When the operation of the heat pump unit 100 is continued depending on the number of rotations, the heating capacity q ′ may decrease. Therefore, the process returns to step S-1 every predetermined time, for example, every hour, the heating capacity q ′ is calculated again, and the heat pump unit 100 is operated with the calculated heating capacity q ′ again, so that the inside of the tank 7 is surely obtained. Necessary hot water storage can be secured.

  According to the embodiment of the present invention, the heating capacity q ′ of the heat pump water heater is reduced by subtracting the heat storage amount in the tank 7 from the target heat storage amount at the time of boiling operation for storing the hot water in the tank 7 with the heat pump water heater. The heating capacity divided by the time from the start time to the end time of the midnight power time zone is multiplied by or added to a predetermined constant, and the operation is started from the start time of the midnight power time zone. The operating time average COP can be improved, and the necessary amount of heat can be secured within the midnight power hours.

  In addition, when the heat pump type hot water heater is operated as in the present embodiment, the operation can be performed in a state where the refrigerant pressure in the air heat exchanger 4 is higher than in the case where the boiling operation is completed in a short time. That is, since the temperature of the refrigerant passing through the air heat exchanger 4 becomes high, frost formation on the air heat exchanger 4 becomes difficult, and the number of times of performing the defrosting operation can be reduced. Therefore, the operation time average COP of the heat pump type hot water heater can be improved as compared with the case where the boiling operation is completed in a short time.

  DESCRIPTION OF SYMBOLS 1 Compressor, 2 Water refrigerant heat exchanger, 3 Expansion valve, 4 Air heat exchanger, 5 Blower fan, 6 Pump, 7 Tank, 7a Hot water inlet, 7b Water intake, 8a-8f Connection piping, 9a Incoming water temperature sensor, 9b Hot water temperature sensor, 9c Outside air temperature sensor, 9d Discharge temperature sensor, 9e Intake temperature sensor, 9f Evaporation temperature sensor, 9g-9j Hot water storage temperature sensor, 10 Measurement control device, 100 Heat pump unit, 101 Refrigeration cycle.

Claims (5)

A refrigerant circuit in which a compressor, a water refrigerant heat exchanger, an expansion valve, and an air heat exchanger are annularly connected;
A hot water supply circuit for storing water heated by the water refrigerant heat exchanger in a tank;
Target heat storage amount calculation means for calculating a target heat storage amount to be stored in the tank, heat storage amount detection means in the tank for detecting the heat storage amount stored in the tank, heating capacity calculation means for calculating the heating capacity of the boiling operation, And an operation control means for controlling the heating operation to the tank,
The heating capacity calculated by the heating capacity calculator is the amount of heat obtained by subtracting the amount of heat stored in the tank detected by the amount of heat stored in the tank detected from the amount of heat stored in the tank from the target amount of stored heat calculated by the target amount of stored heat. A heating capacity obtained by dividing or adding a predetermined constant to the heating capacity divided by the time from the start time to the end time of the power time zone, and the operation control means for controlling the boiling operation is a midnight power time zone A heat pump type hot water heater characterized by starting a boiling operation at the start time of. A refrigerant circuit in which a compressor, a water refrigerant heat exchanger, an expansion valve, and an air heat exchanger are annularly connected;
A hot water supply circuit for storing water heated by the water refrigerant heat exchanger in a tank;
Target heat storage amount calculation means for calculating a target heat storage amount to be stored in the tank, heat storage amount detection means in the tank for detecting the heat storage amount stored in the tank, heating capacity calculation means for calculating the heating capacity of the boiling operation, And an operation control means for controlling the heating operation to the tank,
The heating capacity calculated by the heating capacity calculator is the amount of heat obtained by subtracting the amount of heat stored in the tank detected by the amount of heat stored in the tank detected from the amount of heat stored in the tank from the target amount of stored heat calculated by the target amount of stored heat. When the heating capacity divided by the time from the start time to the end time of the power time zone is multiplied by or added to a predetermined constant, and the heating capacity is equal to or higher than the minimum heating capacity of the refrigerant circuit The operation control means for controlling the boiling operation starts the boiling operation at the start time of the midnight power time zone, and when the heating capacity is smaller than the minimum heating capacity of the refrigerant circuit, the minimum heating capacity is An operation time at which a target heat storage amount can be secured is calculated, and the operation is started with the minimum heating capacity from the operation start time.   The heating capacity is calculated every predetermined time after the start of the boiling operation, and the heating capacity is changed to the heating capacity calculated by the heating capacity calculation means, and the boiling operation is continued. Heat pump water heater.   The defrosting operation is performed during the boiling operation, and after the defrosting operation is completed, the heating capacity is changed to the heating capacity calculated by the heating capacity calculation means, and the boiling operation is continued. The heat pump type water heater according to any one of the above.   The heat pump type hot water heater according to any one of claims 1 to 4, wherein the target heat storage amount calculation means includes a heat storage amount detection means stored in the tank and a necessary heat storage amount calculation means.

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