JP2006046738A - Heat pump hot water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable continuation of hot water storage operation while suppressing the progress of frost formation to an evaporator to prevent a shortage of hot water by detecting the frost forming state of the evaporator and performing, in a case that it is in a predetermined state, a control for forcedly reducing the boiling capability to a hot water storage tank, thereby reducing the operation frequency of a compressor. <P>SOLUTION: This water heater comprises a heat pump cycle 10 having the compressor, a hot water supply heat exchanger 12, an expansion valve 13, and the evaporator 14 which are mutually connected through pipes; the hot water storage tank 21 storing liquid heated by use of the heat pump cycle 10; and a frost forming state detection means 73 detecting the frost forming state of the evaporator 14. Since the boiling capability to the hot water storage tank 21 is forcedly reduced when the frost forming state of the evaporator 14 detected by the detection means 73 is a preset first temperature, the operation frequency of the compressor 11 is reduced, and the hot water storage operation can be continued while suppressing the progress of frost formation to the evaporator 14 to prevent the shortage of hot water. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a heat pump hot water supply apparatus provided with a hot water storage tank.

  Conventionally, hot water supply apparatuses using various heat pump cycles have been proposed. In this device, as a control method at the time of frosting of the evaporator, it is determined whether to give priority to defrosting operation or hot water storage operation according to the amount of unheated water in the hot water storage tank, and defrosting operation A method has been proposed in which the hot water storage is completed quickly by controlling the timing (see, for example, Patent Document 1).

  FIG. 5 is a flowchart showing the timing of entering the defrosting operation of the conventional heat pump water heater described in the publication. In FIG. 5, hot water storage is started when the refrigerant circuit starts operation (step S1).

  Then, it is determined whether or not the hot water storage is completed (step S2). When the hot water storage is completed, the evaporator is defrosted in preparation for the next hot water storage operation (step S3), and then the hot water storage operation is terminated (step S3). Step S4).

  On the other hand, when the hot water storage is not completed, it is determined whether or not there is a defrost request (frost formation) (step S5). At this time, when the defrosting operation is requested, it is determined whether or not the hot water that has not yet been heated in the hot water storage tank (including the hot water that has not reached the predetermined temperature) is equal to or less than a preset amount of water. Is performed (step S6).

If the amount of unheated water used is less than the predetermined amount, mask the request for defrosting operation for a predetermined time, enter the heating priority mode that preferentially stores hot water, start the timer and start the heating priority. The mode is performed for a predetermined time (step S8), and then the defrosting operation is performed (step S7).
JP 2001-255003 A

  However, in the conventional configuration, when the evaporator forms frost at a low outside air temperature, and the use water that has not been heated in the hot water storage tank is less than a preset amount of water, the heating priority mode in which hot water storage is given priority is set. The hot water storage operation is continued. At this time, the control method of the compressor, the pressure reducing device, the circulation pump, etc. is controlled to raise the operating frequency of the inverter and narrow the pressure reducing device because frosting occurs in the evaporator, the hot water supply capacity is lowered, and the hot water temperature is lowered. Therefore, there was a problem that the evaporator further promotes frost formation. In the worst case, the hot water storage operation could not be continued during the heating priority mode.

  The present invention solves the above-described conventional problems, and is a heat pump hot water supply apparatus equipped with a hot water storage tank that detects the frosting state of the evaporator and forcibly raises the hot water storage tank when it reaches a predetermined state. Control is performed to reduce (the amount of heat that can be made into hot water by heating water per unit time).

  On the heat pump cycle side, the operating frequency of the compressor corresponding to the reduced capacity of boiling in the hot water storage tank is reduced, and the amount of heat per unit time absorbed by the evaporator is reduced, so the reduction in evaporation temperature can be suppressed. It is an object of the present invention to provide a heat pump hot water supply device capable of continuing the hot water storage operation while suppressing the progress of frost formation on the evaporator.

  In order to solve the above-described conventional problems, the heat pump hot water supply apparatus of the present invention reduces the ability to forcibly boil the hot water storage tank when the frosting state of the evaporator reaches a preset first temperature.

  As a result, the frosting state of the evaporator is detected, and control is performed to reduce the ability to forcibly boil the hot water storage tank when a predetermined state is reached. It is possible to continue the hot water storage operation while suppressing the progress of frost, thus preventing the hot water from running out.

  The heat pump hot water supply apparatus of the present invention detects the frosting state of the evaporator, and performs control to lower the ability to forcibly boil the hot water storage tank when it reaches a predetermined state, so the operating frequency of the compressor decreases, It becomes possible to continue the hot water storage operation while suppressing the progress of frost formation on the evaporator, and it is possible to prevent hot water from running out.

  A first invention includes a heat pump cycle in which a compressor, a hot water supply heat exchanger, an expansion valve, and an evaporator are connected by piping, and a hot water storage tank that stores a liquid heated by using the heat pump cycle. Ability to provide a frosting state detection means for detecting a frosting state, and forcibly boil the hot water storage tank when the frosting state of the evaporator detected by the frosting state detection means reaches a preset first temperature. Lower.

  Therefore, the frost formation state of the evaporator is detected, and the control to lower the ability to forcibly boil the hot water storage tank when it reaches a predetermined state is performed, so the hot water storage operation is continued while suppressing the progress of frost formation on the evaporator It becomes possible to prevent running out of hot water. In particular, even when the hot water storage tank has a small capacity of, for example, 80 liters, hot water can be prevented from running out.

  According to a second aspect of the present invention, in particular, in the heat pump water heater of the first aspect of the invention, when the frosting state of the evaporator detected by the frosting state detection means reaches the preset first temperature, the hot water storage tank The operating frequency of the compressor is lowered in order to lower the boiling capacity.

  Therefore, it can be quickly reduced to the desired boiling capacity.

  In particular, in the heat pump water heater of the second invention, the third invention includes an outside air temperature sensor that detects an outside air temperature, and the first temperature is determined according to the outside air temperature detected by the outside air temperature sensor. Temperature.

  Accordingly, by detecting the outside air temperature, it is possible to perform an appropriate operation according to the outside air temperature.

  In a fourth aspect of the invention, in particular, in the heat pump hot water supply apparatus of the third aspect of the invention, when the hot water storage operation to the hot water storage tank is completed while the first temperature is continued, the defrost operation is performed to continuously defrost the evaporator. I do.

  Therefore, since the evaporator is defrosted in preparation for the next hot water storage operation, a high capacity and high COP operation is possible.

  In particular, in the heat pump water heater of the third invention, the fifth aspect of the present invention is configured to simultaneously perform a hot water storage operation, a hot water supply operation, a pouring operation, or a bath heating operation to the hot water storage tank while the first temperature is continued. When the hot water supply operation, the pouring operation, or the bath heating operation is completed, the hot water storage operation to the hot water storage tank is stopped and the defrosting operation for defrosting the evaporator continuously is performed.

  Accordingly, when there is no load and there is no fear of running out of hot water, priority is given to the defrosting operation of the evaporator, so that the remaining hot water storage operation can be performed with high capacity and high COP operation.

  In a sixth aspect of the invention, in particular, in the third aspect of the invention, when the frosting state of the evaporator detected by the frosting state detection means reaches a preset second temperature while the first temperature is being continued. Perform defrosting operation.

  Therefore, by giving priority to the defrosting operation of the evaporator, the remaining hot water storage operation can be performed with high capacity and high COP operation.

  In a seventh aspect of the invention, in particular, in any one of the fourth to sixth aspects of the invention, when the defrosting operation is completed, the ability to boil the hot water storage tank is restored.

  Therefore, the next time hot water storage operation is performed, high capacity and high COP operation is possible.

  In particular, an eighth invention includes a plurality of heat pump cycles in any one of the first to seventh inventions.

  Therefore, the number of operating heat pump cycles can be switched according to the boiling capacity, and efficient operation can be performed with a wide range of capabilities.

  In the ninth invention, in particular, in any one of the first to seventh inventions, the refrigerant used for the heat pump cycle is carbon dioxide, and the high pressure side is operated in a state exceeding the critical pressure.

  Accordingly, hot water can be generated, and when a hot water storage tank is used in combination, hot water can be stored, so that the hot water storage tank can be reduced in size.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiment.

(Embodiment 1)
FIG. 1 is a circuit configuration diagram of the heat pump water heater in the first embodiment of the present invention. FIG. 2 is a flowchart of hot water storage operation control of the heat pump hot water supply apparatus in the first embodiment of the present invention.

  In FIG. 1, the refrigeration circuit of the heat pump hot-water supply apparatus in the 1st Embodiment of this invention is demonstrated.

  The heat pump cycle 10 is configured by connecting a compressor 11, a hot water supply heat exchanger 12, an expansion valve 13, and an evaporator 14 in this order by piping. The heat pump cycle 10 includes a bypass circuit 15 that bypasses the hot water supply heat exchanger 12, and the bypass circuit 15 is provided with a control valve 16. Further, a fan 17 for blowing air to the evaporator 14 corresponding to the heat pump cycle 10 is provided. Further, an evaporator outlet temperature sensor 18 and an outside air temperature sensor 19 are installed.

  The heat pump hot water supply apparatus according to the present embodiment preferably uses carbon dioxide as a refrigerant and is operated on the high pressure side in a state exceeding the critical pressure.

  Next, the hot water supply circuit of the heat pump hot water supply apparatus in the first embodiment of the present invention will be described.

  A first bottom pipe 22 of the hot water storage tank 21 is connected to a water supply pipe 24 such as a water pipe via a pressure reducing valve 23. One of the water discharge pipes 25 branched from the first bottom pipe 22 of the hot water storage tank 21 is connected to the first mixing valve 27 via the check valve 26, and the other is connected to the first mixing valve 27 via the check valve 28. The two mixing valves 29 are connected. One of the first upper pipes 30 of the hot water storage tank 21 is connected to the first mixing valve 27 via the check valve 31, and the other is connected to the second mixing valve 29. The outlet pipe 25 and the first upper pipe 30 of the hot water storage tank 21 are mixed by a first mixing valve 27 via a check valve 26 and a check valve 31, respectively, and a faucet 32 for hot water supply such as a kitchen or a washroom. It is connected to the. The hot water supply circuit is provided with a flow rate sensor 33 for detecting the flow rate of a hot water supply faucet 32 such as a kitchen or a washroom.

  Next, a hot water storage circuit of the heat pump hot water supply apparatus in the first embodiment of the present invention will be described.

  The second bottom pipe 34 of the hot water storage tank 21 is connected to the inflow side of the water pipe 12 </ b> A of the hot water supply heat exchanger 12 via the first circulation pump 35. Further, the second upper pipe 36 of the hot water storage tank 21 is connected to the outflow side of the water pipe 12 </ b> A through the three-way valve 37. The third bottom piping 38 of the hot water storage tank 21 is connected to the three-way valve 37. The hot water storage tank 21 according to the embodiment of the present invention is a stacked hot water storage tank, and is configured so that stirring in the tank is prevented and high temperature water is accumulated at the top and low temperature water is accumulated at the bottom.

  Next, the bath heating circuit of the heat pump hot water supply apparatus in the first embodiment of the present invention will be described.

  The fourth bottom piping 41 of the hot water storage tank 21 is connected to the third upper piping 44 of the hot water storage tank 21 via the second circulation pump 42 and the first water piping 43 </ b> A of the bath heat exchanger 43.

  The second water pipe 43 </ b> B of the bath heat exchanger 43 is connected to a bathtub circulation pipe 52 including a third circulation pump 51. Further, a water level sensor 53 is provided between the bathtub 50 and the circulation pump 51 in order to detect the amount of hot water in the bath.

  In addition, pouring to the bathtub 50 can be performed using the pouring pipe 61 connected to the downstream piping of the second mixing valve 29. The pouring pipe 61 is connected to the bathtub circulation pipe 52. The pouring pipe 61 is provided with a pouring valve 62. This pouring circuit is provided with a flow rate sensor 63 for detecting the pouring flow rate to the bathtub 50.

  The remote controller 71 instructs the hot water temperature from the faucet 32, the boiling temperature of the bathtub 50, the start of boiling, and the like, and controls the heat pump cycle 10 by the control means 72 based on the instructions from the remote controller 71. . The control means 72 includes frosting state detection means 73. The detection values of various sensors are input to the control means 72, and the control of the compressor 11, the expansion valve 13, and the fan 17 is controlled by the results output from the control means 72.

  Next, the hot water storage operation of the heat pump hot water supply apparatus in the first embodiment of the present invention will be described.

  When the remaining hot water sensor (not shown) installed in the hot water storage tank 21 determines that the remaining hot water amount is small, the heat pump cycle 10 starts operation.

  The refrigerant compressed by the compressor 11 dissipates heat in the hot water supply heat exchanger 12, is depressurized by the expansion valve 13, absorbs heat in the evaporator 14, and is sucked into the compressor 11 in a gas state. At this time, the control valve 16 is closed and no refrigerant flows into the bypass circuit 15.

  Water from the hot water storage tank 21 is passed through the second bottom piping 34 of the hot water storage tank 21 by the first circulation pump 35, led to the water piping 12 </ b> A of the hot water supply heat exchanger 12, and via the three-way valve 37, the hot water storage tank 21. Flow into. In the three-way valve 37, whether to connect to the second upper pipe 36 of the hot water storage tank 21 or to the third bottom pipe 38 of the hot water storage tank 21 is determined on the outlet side of the water pipe 12A of the hot water supply heat exchanger 12. At a temperature of (not shown).

  Next, the hot water supply operation of the heat pump hot water supply apparatus in the first embodiment of the present invention will be described.

  When the faucet 32 is opened, the hot water stored in the hot water storage tank 21 passes through the first upper pipe 30 and the check valve 31 of the hot water storage tank 21 and is guided to one of the first mixing valves 27. The water is fed to the other side of the first mixing valve 27 through the water supply pipe 24 such as a pipe, the pressure reducing valve 23, the water outlet pipe 25, and the check valve 26, and then mixed to the faucet 32.

  Next, the defrosting operation of the heat pump water heater in the first embodiment of the present invention will be described. When the control means 72 detects a defrosting instruction, the heat pump cycle 10 starts the defrosting operation.

  As an example of the defrosting operation, first, the control valve 16 is opened. The refrigerant compressed by the compressor 11 passes through the hot water supply heat exchanger 12, the control valve 16, the bypass circuit 15, the expansion valve 13, the high-temperature refrigerant flows to the evaporator 14, defrosts, and then compressed. Inhaled by the machine 11. Further, the fan 17 for blowing air to the evaporator 14 is stopped. The hot water supply circulation pump 35 is stopped so as not to dissipate heat.

  Various defrosting methods are conventionally known, and it goes without saying that these methods can also be applied in the present invention.

  Next, hot water storage operation control of the heat pump water heater in the first embodiment of the present invention will be described with reference to the flowchart of FIG.

  Here, the case where only hot water storage operation is performed will be described. When it is determined by the remaining hot water sensor (not shown) installed in the hot water storage tank 21 that the remaining hot water amount is small, the heat pump cycle 10 starts operation and the compressor 11 starts (step 1). At this time, the boiling capacity (required capacity) is determined, and the operation frequency (for example, 66 Hz) of the compressor 11 is set to start the operation so that the boiling capacity is 6 kW, for example. The opening degree of the expansion valve 13 and the flow rate of the first circulation pump 35 are set together with the operation frequency of the compressor 11.

  Here, the boiling capacity is obtained by the flow rate of hot water in the hot water supply circuit side, that is, the water pipe 12A of the hot water supply heat exchanger 12 and the temperature difference of the hot water. Accordingly, the boiling capacity corresponds to the amount of heat per unit time given from the heat pump cycle side to the tapping circuit side.

  Next, it is determined whether the temperature of the evaporator 14 is lower than a first temperature (for example, −1 ° C.) by the evaporator outlet temperature sensor 18 which is the frosting state detecting means 73 (step 2). Here, the first temperature is determined by the outside air temperature detected by the outside air temperature sensor 19, for example, as shown in (Table 1).

  Next, when the temperature of the evaporator 14 is lower than the first temperature (for example, −1 ° C.), in order to forcibly lower the boiling capacity (required capacity) (for example, 5 kW), the compressor 11 operating frequency (for example, 55 Hz) is changed. In addition, the opening degree of the expansion valve 13 and the flow rate of the first circulation pump 35 are changed together with the operation frequency of the compressor 11. (Step 3). Here, if the frequency is lowered to lower the boiling capacity, the refrigerant circulation amount on the heat pump cycle side is lowered. As a result, the amount of heat per unit time absorbed by the evaporator is reduced, so that a reduction in evaporation temperature can be suppressed and hot water storage operation can be continued.

  Next, it is determined whether the hot water storage operation is completed (step 4). In step 4, when the hot water storage operation is completed, the defrosting operation is performed (step 5). When the defrosting operation is completed, the boiling capacity (required capacity) forcibly lowered in step 3 is returned to the original (for example, increased to 6 kW) (step 6).

  Next, in step 4, when the hot water storage operation is continued, it is determined by the evaporator outlet temperature sensor 18 whether the temperature of the evaporator 14 is lower than a second temperature (for example, −4 ° C.) (step 7). ). Here, the second temperature is determined by the outside air temperature detected by the outside air temperature sensor 19, for example, as shown in (Table 1).

  Next, in Step 7, when the temperature of the evaporator 14 is lower than the second temperature (for example, −4 ° C.), the hot water storage operation is stopped and the defrosting operation is performed (Step 8). When the defrosting operation is completed, the boiling capacity (required capacity) forcibly lowered in step 3 is returned to the original (for example, increased to 6 kW) (step 6). Moreover, when the temperature of the evaporator 14 is 2nd temperature (for example, -4 degreeC) or more, it transfers to step 4.

  As described above, the heat pump water heater of the present embodiment detects the frosting state of the evaporator 14, and when it reaches a predetermined state, the operating frequency of the compressor 11 is lowered in order to reduce the ability to forcibly boil the hot water storage tank 21. The hot water storage operation can be continued while suppressing the progress of frost formation on the evaporator 14, and it is possible to prevent hot water from running out.

  In addition, as a method of lowering the boiling capacity, the method of assigning the operating frequency of the specific compressor 11 according to the required capacity (for example, 66 Hz for 6 kW, 55 Hz for 5 kW) has been described. So that the operating frequency of the compressor 11 may be lowered.

  In addition, the control for forcibly lowering the boiling capacity has been described as being performed only once (for example, decreasing from 6 kW to 5 kW), but the control for decreasing in steps (for example, from 6 kW to 5 kW, 4.5 kW, 4 kW) is performed a plurality of times. You may go.

  FIG. 3 is a time chart showing an example of the evaporator temperature of the heat pump water heater in the first embodiment of the present invention.

  Here, the case where only hot water storage operation is performed will be described. When the remaining hot water sensor (not shown) installed in the hot water storage tank 21 determines that the amount of remaining hot water is small, the heat pump cycle 10 starts operation and the compressor 11 starts. At this time, the boiling capacity (required capacity) is determined and set to 6 kW, for example, and the operation is started at the compressor operating frequency (for example, 66 Hz) corresponding to this capacity. Further, the opening degree of the expansion valve and the flow rate of the first circulation pump are also set to the opening degree and the flow rate corresponding to this ability.

  When the outside air temperature is low, the evaporator 14 is frosted, the evaporator temperature gradually decreases, and when the temperature falls below the first temperature (for example, −1 ° C.) at time t1, the boiling capacity (required capacity) is increased. For example, 5 kW is set so as to forcibly lower, and the hot water storage operation is continued. Here, in order to lower the boiling capacity (required capacity), the operating frequency of the compressor 11 is changed to an operating frequency (for example, 55 Hz) corresponding to the required capacity. Further, the opening degree of the expansion valve 13 and the flow rate of the first circulation pump 35 are also reset. Therefore, the operating frequency of the compressor is lowered, and the speed at which the evaporator temperature is lowered due to frost formation is reduced.

  When the temperature becomes lower than the second temperature (for example, −4 ° C.) at time t2, the hot water storage operation is stopped and the defrosting operation is started. When the defrosting operation is completed at time t3, the hot water storage operation is resumed. Here, the setting of the boiling capacity is returned to a predetermined value (for example, 6 kW). When the temperature becomes lower than the first temperature (for example, −1 ° C.) at time t4, the boiling capacity is forcibly lowered, for example, set to 5 kW, and the hot water storage operation is continued. When the hot water storage operation is completed at time t5, the defrosting operation is started.

  In the present embodiment, when the frosting state of the evaporator reaches a preset first temperature, the control is performed to reduce the ability (required ability) to forcibly boil the hot water storage tank. The same effect can be obtained as control for raising the boiling temperature.

  In the present embodiment, the case where carbon dioxide is used as the refrigerant has been described. However, other refrigerants such as R410A refrigerant and HC refrigerant may be used as the refrigerant.

  Moreover, although this Embodiment demonstrated using the heat pump hot-water supply apparatus provided with the heat pump cycle 10, you may use two or more heat pump cycles.

  Moreover, the heat exchanger 43 for baths can also be utilized as a heat exchanger for heating such as floor heating or hot air equipment.

(Embodiment 2)
FIG. 4 is a flowchart of hot water storage operation control of the heat pump water heater in the second embodiment of the present invention.

  Here, a case where the hot water storage operation and the hot water supply operation are performed simultaneously will be described. When the faucet 32 is opened, the hot water stored in the hot water storage tank 21 and the water supplied from the water supply pipe 24 such as a water pipe are mixed by the first mixing valve 27 and the hot water supply operation is started. When the hot water supply operation is started and the remaining hot water sensor (not shown) installed in the hot water storage tank 21 determines that the amount of remaining hot water is small, the heat pump cycle 10 starts operation and the compressor 11 starts (step 1). ). At this time, the boiling capacity (required capacity) is determined, and the operation frequency (for example, 66 Hz) of the compressor 11 is set to start the operation so that the boiling capacity is 6 kW, for example. The opening degree of the expansion valve 13 and the flow rate of the first circulation pump 35 are set together with the operation frequency of the compressor 11.

  Next, it is determined whether the temperature of the evaporator 14 is lower than a first temperature (for example, −1 ° C.) by the evaporator outlet temperature sensor 18 which is the frosting state detecting means 73 (step 2). Here, the first temperature is determined by the outside air temperature detected by the outside air temperature sensor 19, for example, as shown in (Table 1).

  Next, when the temperature of the evaporator 14 is lower than the first temperature (for example, −1 ° C.), in order to forcibly lower the boiling capacity (required capacity) (for example, 5 kW), the compressor 11 operating frequency (for example, 55 Hz) is changed. The opening of the expansion valve 13 and the flow rate of the first circulation pump 35 are changed together with the operating frequency of the compressor 11 (step 3). Here, if the frequency is lowered to lower the boiling capacity, the refrigerant circulation amount on the heat pump cycle side is lowered. As a result, the amount of heat per unit time absorbed by the evaporator is reduced, so that a reduction in evaporation temperature can be suppressed and hot water storage operation can be continued.

  Next, it is determined whether the hot water supply operation has been completed (step 4). In step 4, when the hot water supply operation is completed, a defrosting operation is performed (step 5). When the defrosting operation is completed, the boiling capacity (required capacity) forcibly lowered in step 3 is returned to the original (for example, increased to 6 kW) (step 6).

  Next, when the hot water supply operation is continued in step 4, it is determined whether the hot water storage operation is completed (step 7). In step 7, when the hot water storage operation is completed, a defrosting operation is performed (step 8). When the defrosting operation is completed, the boiling capacity (required capacity) lowered in Step 3 is restored (for example, increased to 6 kW) (Step 6).

  Next, in step 7, when the hot water storage operation is not completed, it is determined by the evaporator outlet temperature sensor 18 whether the evaporator temperature is lower than a second temperature (for example, −4 ° C.) (step 9). Here, the second temperature is determined by the outside air temperature detected by the outside air temperature sensor 19, for example, as shown in (Table 1).

  Next, in step 9, when the evaporator temperature is lower than a second temperature (for example, −4 ° C.), a defrosting operation is performed (step 10). When the defrosting operation is completed, the boiling capacity (required capacity) lowered in Step 3 is restored (for example, increased to 6 kW) (Step 6). In Step 10, when the evaporator temperature is equal to or higher than the second temperature (for example, −4 ° C.), the process proceeds to Step 4.

  As described above, the heat pump hot water supply apparatus according to the second embodiment of the present invention detects the frosting state of the evaporator 14 and compresses it to reduce the ability to forcibly raise the hot water storage tank 21 when it reaches a predetermined state. The hot water storage operation and the hot water supply operation can be continued at the same time while reducing the operation frequency of the machine 11 and suppressing the progress of frost formation on the evaporator 14, thereby preventing the hot water from running out.

  In addition, as a method of lowering the boiling capacity, the method of assigning the operating frequency of the specific compressor 11 according to the required capacity (for example, 66 Hz for 6 kW, 55 Hz for 5 kW) has been described. So that the operating frequency of the compressor 11 may be lowered.

  In addition, the control for forcibly lowering the boiling capacity has been described as being performed only once (for example, decreasing from 6 kW to 5 kW), but the control for decreasing in steps (for example, from 6 kW to 5 kW, 4.5 kW, 4 kW) is performed a plurality of times. You may go.

  Further, in the present embodiment, when the frosting state of the evaporator reaches a preset first temperature, the control for forcibly boiling the hot water storage tank is performed. However, the boiling temperature is forcibly set to the hot water storage tank. The same effect can be obtained as the control for increasing the speed.

  In the present embodiment, the hot water storage operation and the hot water supply operation are described simultaneously. However, the same effect can be obtained by the simultaneous operation of the hot water storage operation and the pouring operation and the simultaneous operation of the hot water storage operation and the bath heating operation.

  As described above, the heat pump hot water supply device according to the present invention detects the frosting state of the evaporator and performs control to lower the ability to forcibly boil the hot water storage tank when it reaches a predetermined state. Since the operating frequency is reduced and hot water storage operation can be continued while suppressing the progress of frost formation on the evaporator, hot water can be prevented from running out, so it can also be applied to safety improvement applications such as heating using hot water. .

The circuit block diagram of the heat pump hot-water supply apparatus in Embodiment 1 of this invention Flowchart of hot water storage operation control of heat pump hot water supply apparatus in Embodiment 1 of the present invention Time chart which shows an example of the evaporator temperature of the heat pump hot-water supply apparatus in Embodiment 1 of this invention Flowchart of hot water storage operation control of heat pump hot water supply apparatus in Embodiment 2 of the present invention The flowchart which shows the timing which enters into the defrost operation of the conventional heat pump water heater

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Heat pump cycle 11 Compressor 12 Heat exchanger for hot water supply 13 Expansion valve 14 Evaporator 21 Hot water storage tank 73 Frosting state detection means

Claims (9)

A heat pump cycle in which a compressor, a heat exchanger for hot water supply, an expansion valve, and an evaporator are connected by piping, and a hot water storage tank that stores liquid heated using the heat pump cycle, and detects the frosting state of the evaporator The heat pump is provided with a frosting state detecting means for reducing the ability to boil the hot water storage tank when the frosting state of the evaporator detected by the frosting state detecting means reaches a preset first temperature. Hot water supply device. The operation frequency of the compressor is lowered to lower the ability to boil the hot water storage tank when the frosting state of the evaporator detected by the frosting state detection means reaches the preset first temperature. The heat pump hot water supply apparatus according to 1. The heat pump hot water supply according to claim 2, further comprising an outside air temperature sensor for detecting an outside air temperature, wherein the first temperature is a temperature determined according to the outside air temperature detected by the outside air temperature sensor. apparatus. 4. The heat pump hot-water supply apparatus according to claim 3, wherein when the hot water storage operation to the hot water storage tank is completed while the first temperature is continued, the defrost operation for continuously defrosting the evaporator is performed. When hot water storage operation and hot water supply operation, pouring operation or bath heating operation are simultaneously performed in the hot water storage tank while the first temperature is continued, the hot water supply operation, pouring operation or bath heating operation is completed. Then, the heat pump hot water supply apparatus according to claim 3, wherein the hot water storage operation to the hot water storage tank is stopped and the defrosting operation for continuously defrosting the evaporator is performed. The defrosting operation is performed when the frosting state of the evaporator detected by the frosting state detection means reaches a preset second temperature while the first temperature is continued. The heat pump hot-water supply apparatus of description. The heat pump hot water supply device according to any one of claims 4 to 6, wherein when the defrosting operation is completed, the boiling capacity of the hot water storage tank is increased. The heat pump hot-water supply apparatus of any one of Claims 1-7 provided with two or more of the said heat pump cycles. The heat pump hot water supply apparatus according to any one of claims 1 to 7, wherein the refrigerant used in the heat pump cycle is carbon dioxide, and the high pressure side is operated in a state exceeding a critical pressure.

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