JP5682552B2 - Heat pump water heater - Google Patents

Description

  The present invention relates to a heat pump water heater that performs a defrost operation.

  A heat pump type hot water heater is a device that heats low temperature water taken out from a tank by heat exchange with a refrigerant in a water heat exchanger and returns it to the tank. The water heat exchanger, compressor, and decompression means It has a refrigerant circuit including an electric valve and an air heat exchanger as an evaporator.

  When the temperature is low, frost formation may occur in the air heat exchanger during boiling operation, and the capacity of the air heat exchanger may be reduced. Therefore, conventionally, in order to remove the frost formation of the air heat exchanger, the heat pump type water heater is configured to perform a defrost operation (defrost operation).

For example, there is a heat pump type water heater that starts a defrost operation when the temperature of the air heat exchanger becomes equal to or lower than a predetermined temperature.
Further, for example, there is a heat pump type hot water heater that starts a defrost operation when the boiling capacity continuously decreases after activation (see, for example, Patent Document 1). The boiling capacity here refers to the temperature difference between the temperature of hot water flowing into the water heat exchanger (incoming water temperature) and the temperature of hot water flowing out (temperature of the tapping water), and the hot water in the tank is supplied to the water heat exchanger. It is a value calculated based on the product of the pump output (that is, the flow rate of hot water passing through the water heat exchanger).

JP 2003-222392 A

However, in the heat pump water heater that starts the defrost operation when the temperature of the air heat exchanger becomes equal to or lower than the predetermined temperature, the predetermined temperature is set low to avoid erroneous detection. Therefore, even if snow is generated in the air heat exchanger during startup, the temperature may be higher than a predetermined temperature. In this case, the defrosting operation is not performed, and the operation in which the hot water temperature does not reach the target hot water temperature is performed for a long time.
In addition, if the air heat exchanger is snowing before starting the boiling operation due to factors such as blowing snow, the boiling capacity is already low at the time of startup and the boiling capacity does not decrease after startup. In the heat pump water heater that starts the defrost operation when the upper capacity continuously decreases, the defrost operation may not be performed. As a result, an operation in which the hot water temperature does not reach the target hot water temperature is performed for a long time while snow is generated in the air heat exchanger.

  Then, an object of this invention is to provide the heat pump type hot water heater which can prevent the driving | running which does not reach the target hot water temperature while the boiling capacity is low, and is performed for a long time.

  In order to solve the above-described problem, a heat pump hot water heater according to a first invention includes a compressor, a water heat exchanger for heating hot water, a motor circuit, and a refrigerant circuit in which an air heat exchanger is connected in order, A heat pump type water heater comprising a water heat exchanger, a tank and a boiling circuit in which a pump for supplying hot water from the tank to the water heat exchanger is connected in order, and the start determination of the defrost operation is performed by the pump The condition is that the state in which the flow rate in the tank is equal to or less than a predetermined pump flow rate and the temperature difference between the tapping temperature and the target tapping temperature is equal to or greater than the predetermined tapping temperature difference is continued for a predetermined pump determination time. To do.

In this heat pump type hot water supply apparatus, the defrosting operation is started when the hot water temperature is lower than the target hot water temperature by a predetermined temperature or more despite the control of increasing the hot water temperature by reducing the pump flow rate. Therefore, defrosting operation can be started when frost or snow is generated in the air heat exchanger before startup and the boiling capacity at startup is low, so the tapping temperature remains at the target tapping temperature while the boiling capacity remains low. It is possible to prevent the operation that does not reach from continuing for a long time.
The “temperature difference between the tapping temperature and the target tapping temperature” is a value obtained by subtracting the tapping temperature from the target tapping temperature, and is a positive value when the tapping temperature is lower than the target tapping temperature. .

  In the heat pump type hot water heater according to the second invention, in the first invention, the start determination of the defrost operation is such that the opening degree of the motor-operated valve is equal to or less than a predetermined motor-operated valve opening degree and the discharge temperature of the compressor It is characterized in that it is performed when a state in which the temperature difference from the target discharge temperature corresponding to the target hot water temperature is not less than a predetermined discharge temperature difference continues for a predetermined motor-operated valve determination time.

In this heat pump type water heater, even when the pump flow rate is larger than a predetermined pump flow rate, the defrost operation is started when the motor-operated valve opening is small and the discharge temperature is low. Therefore, the defrosting operation can be started more reliably when snow or frosting occurs than when the motor-operated valve opening and the discharge temperature are not used for the determination.
The “temperature difference between the discharge temperature and the target discharge temperature” is a value obtained by subtracting the discharge temperature from the target discharge temperature, and is a positive value when the discharge temperature is lower than the target discharge temperature. .

  A heat pump type water heater according to a third aspect of the present invention includes a compressor, a water heat exchanger for heating hot water, a refrigerant circuit in which an electric valve and an air heat exchanger are connected in order, the water heat exchanger, the tank, and the A heat pump type water heater having a boiling circuit in which a pump for supplying hot water from a tank to the water heat exchanger is connected in order, and the defrost operation start determination is performed when the opening degree of the motor-operated valve is a predetermined electric motor When the valve opening is less than the valve opening and the temperature difference between the discharge temperature of the compressor and the target discharge temperature corresponding to the target hot water temperature is equal to or greater than the predetermined discharge temperature difference, continues for a predetermined motor-operated valve determination time It is characterized by being performed.

  In this heat pump type hot water heater, the defrost operation is performed when the discharge temperature is lower than the target discharge temperature by a predetermined temperature or more despite the control of increasing the discharge temperature of the compressor by reducing the motor valve opening degree. Start. Therefore, defrosting operation can be started when frost or snow is generated in the air heat exchanger before startup and the boiling capacity at startup is low. It is possible to prevent the operation that does not reach the temperature from continuing for a long time.

  A heat pump water heater according to a fourth aspect of the present invention includes a compressor, a water heat exchanger for heating hot water, a refrigerant circuit in which an electric valve and an air heat exchanger are connected in order, the water heat exchanger, the tank, and the A heat pump type water heater provided with a boiling circuit in which a pump for supplying hot water from a tank to the water heat exchanger is connected in order, and the determination of the start of defrost operation is such that the flow rate in the pump is equal to or less than a predetermined pump flow rate And the state in which the temperature difference between the tapping temperature and the target tapping temperature is equal to or greater than a predetermined tapping temperature difference continues for a predetermined pump determination time, and the opening degree of the motor-operated valve is equal to or less than a predetermined motor valve opening degree. And when the temperature difference between the discharge temperature of the compressor and the target discharge temperature corresponding to the target hot water temperature is equal to or greater than a predetermined discharge temperature difference is continued for a predetermined motor-operated valve determination time. Features To.

In this heat pump type hot water heater, although the pump flow rate and the motorized valve opening degree are reduced to increase the hot water temperature and the discharge temperature, the hot water temperature and the discharge temperature are more than a predetermined temperature than the respective target temperatures. If low, start defrost operation. Therefore, defrosting operation can be started when frost or snow is generated in the air heat exchanger before startup and the boiling capacity at startup is low. It is possible to prevent the operation that does not reach the temperature from continuing for a long time.
Further, erroneous determination can be prevented as compared with the case where the pump flow rate and the hot water temperature are not used for the determination, or when the motor-operated valve opening degree and the discharge temperature are not used. In addition, the erroneous determination in this specification is to determine that the defrost operation is started when the snow frost or the frost is hardly generated and the defrost operation is unnecessary.

  A heat pump hot water heater according to a fifth aspect of the present invention is the heat pump type hot water heater according to any one of the first to fourth aspects of the present invention, wherein the defrosting operation start determination is performed once after the defrosting operation has not been performed. It is characterized by that.

  In this heat pump type water heater, even if frost or snow is generated in the air heat exchanger before starting, frost or snow is removed if defrosting is performed even once after starting. It is not necessary to perform the start determination after the defrost operation. Therefore, by performing the start determination only when the defrost operation is not performed after being activated, unnecessary determination can be eliminated and erroneous determination can be prevented.

  The heat pump type hot water heater according to a sixth aspect of the present invention is characterized in that, in any one of the first to fifth aspects, the start determination of the defrost operation is performed when the outside air temperature is started at a predetermined temperature or lower. And

  In this heat pump type water heater, when the outside air temperature at the time of start-up is high, frost or snow is not generated in the air heat exchanger at the time of start-up, and therefore it is not necessary to perform the start determination. Therefore, by performing the start determination only when the temperature is lower than a predetermined temperature at which there is a risk of snowfall, unnecessary determination can be eliminated and erroneous determination can be prevented.

  In any one of the first to sixth inventions, the heat pump type hot water heater according to a seventh aspect of the invention is such that the defrost operation start determination is such that the temperature of the air heat exchanger is equal to or lower than a predetermined heat exchanger temperature, and It is characterized in that it is performed when a predetermined operation time is continued after startup.

In this heat pump type water heater, when the temperature of the air heat exchanger is high, frost or snow has not occurred in the air heat exchanger, so the start determination is performed only when the temperature of the air heat exchanger is equal to or lower than a predetermined temperature. By performing the above, unnecessary determination can be eliminated and erroneous determination can be prevented.
Further, even if frost or snow is not generated in the air heat exchanger at the time of startup, the temperature, the hot water temperature, and the discharge temperature of the air heat exchanger may be low immediately after the startup. Therefore, erroneous determination can be prevented by performing the start determination after a predetermined operation time has elapsed after startup and the temperature of the air heat exchanger, the tapping temperature and the discharge temperature have stabilized.

  As described above, according to the present invention, the following effects can be obtained.

  In the first aspect of the invention, the defrosting operation is started when the tapping temperature is lower than the target tapping temperature by a predetermined temperature or more despite the control of increasing the tapping temperature by decreasing the pump flow rate. Therefore, defrosting operation can be started when frost or snow is generated in the air heat exchanger before startup and the boiling capacity at startup is low, so the tapping temperature remains at the target tapping temperature while the boiling capacity remains low. It is possible to prevent the operation that does not reach from continuing for a long time.

  In the second invention, even if the pump flow rate is larger than the predetermined pump flow rate, the defrost operation is started when the motor-operated valve opening is small and the discharge temperature is low. Therefore, the defrosting operation can be started more reliably when snow or frosting occurs than when the motor-operated valve opening and the discharge temperature are not used for the determination.

  In the third aspect of the invention, the defrost operation is started when the discharge temperature is lower than the target discharge temperature by a predetermined temperature or more despite the control of increasing the discharge temperature of the compressor by reducing the opening degree of the electric valve. To do. Therefore, defrosting operation can be started when frost or snow is generated in the air heat exchanger before startup and the boiling capacity at startup is low. It is possible to prevent the operation that does not reach the temperature from continuing for a long time.

In the fourth invention, the hot water temperature and the discharge temperature are lower than the respective target temperatures by a predetermined temperature or more, although the pump flow rate and the electric valve opening are reduced to increase the hot water temperature and the discharge temperature. If so, start defrosting. Therefore, defrosting operation can be started when frost or snow is generated in the air heat exchanger before startup and the boiling capacity at startup is low. It is possible to prevent the operation that does not reach the temperature from continuing for a long time.
Further, erroneous determination can be prevented as compared with the case where the pump flow rate and the hot water temperature are not used for the determination, or when the motor-operated valve opening degree and the discharge temperature are not used. The erroneous determination is to determine that the defrost operation is started when no snow or frost has occurred.

  In the fifth invention, even if frost or snow has occurred in the air heat exchanger before startup, if defrost operation is performed even once after startup, frost or snow is removed, There is no need to perform the start determination after the defrost operation. Therefore, by performing the start determination only when the defrost operation is not performed after being activated, unnecessary determination can be eliminated and erroneous determination can be prevented.

  In 6th invention, when the external temperature at the time of starting is high, since the frost or the snow does not arise in the air heat exchanger at the time of starting, it is not necessary to perform the said start determination. Therefore, by performing the start determination only when the temperature is lower than a predetermined temperature at which there is a risk of snowfall, unnecessary determination can be eliminated and erroneous determination can be prevented.

In the seventh invention, when the temperature of the air heat exchanger is high, frost or snow has not occurred in the air heat exchanger, so the start determination is performed only when the temperature of the air heat exchanger is equal to or lower than a predetermined temperature. By doing so, unnecessary judgments can be eliminated and erroneous judgments can be prevented.
Further, even if frost or snow is not generated in the air heat exchanger at the time of startup, the temperature, the hot water temperature, and the discharge temperature of the air heat exchanger may be low immediately after the startup. Therefore, erroneous determination can be prevented by performing the start determination after a predetermined operation time has elapsed after startup and the temperature of the air heat exchanger, the tapping temperature and the discharge temperature have stabilized.

It is a piping system diagram of the heat pump type hot water heater according to the first embodiment of the present invention. It is a graph which shows the relationship between the air heat exchanger temperature and the elapsed time after starting, and the start determination conditions of a defrost driving | operation. It is a flowchart of the 1st determination conditions of 1st Embodiment of this invention. It is a flowchart of the 1st determination conditions of 2nd Embodiment of this invention. It is a flowchart of the 1st determination conditions of 3rd Embodiment of this invention.

<First Embodiment>
Hereinafter, a first embodiment of the present invention will be described.
As shown in FIG. 1, the heat pump type water heater 1 of the present embodiment is an apparatus for supplying hot water to a hot water supply terminal, and includes a hot water supply unit 3 having a tank 31 for storing the hot water supplied to the hot water supply terminal. The heat pump unit 2 for heating the hot water in the tank 31 is provided. The heat pump water heater 1 performs a boiling operation for heating the hot water stored in the tank 31 and also performs a boiling operation in order to remove frost or snow attached to the air heat exchanger 14 of the heat pump unit 2. During the course, the boiling operation is temporarily stopped and the defrost operation is performed.

[Configuration of heat pump unit 2]
The heat pump unit 2 has a refrigerant circuit 4 in which a refrigerant (for example, CO ₂ ) circulates. The refrigerant circuit 4 includes a compressor 11, a water heat exchanger 12 for heating hot water, an electric valve 13, an air heat exchanger 14, and a pipe connecting them in order. The refrigerant circuit 4 includes a liquid gas heat exchanger 16 for exchanging heat between a high-temperature and high-pressure refrigerant coming out of the water heat exchanger 12 and a cold and low-pressure refrigerant coming out of the air heat exchanger 14.

  In the refrigerant circuit 4, the refrigerant compressed by the compressor 11 is supplied to the water heat exchanger 12 and cooled by heat exchange with warm water in the water heat exchanger 12, and then in the liquid gas heat exchanger 16. It is further cooled. Thereafter, the refrigerant is depressurized in the motor-operated valve 13, and then heated by the heat exchange with the outside air in the air heat exchanger 14 and returns to the compressor 11.

  The air heat exchanger 14 is provided with a fan 15 for adjusting the capacity of the air heat exchanger 14. Moreover, the opening degree of the motor operated valve 13 can be changed. By reducing the opening degree of the motor-operated valve 13, the temperature of the refrigerant discharged from the compressor 11 (discharge temperature) increases. The reverse is true when the opening is increased.

  The heat pump unit 2 also detects the temperature (discharge temperature) of the heat exchange thermistor 21 for detecting the temperature (air heat exchange temperature) of the air heat exchanger 14 and the refrigerant discharged from the compressor 11. It has a discharge thermistor 22 and an outside air thermistor 23 for detecting the outside air temperature.

[Configuration of hot water supply unit 3]
The hot water supply unit 3 includes a boiling circuit 5 and a hot water supply circuit 6 connected via a tank 31. The tank 31 has a hot water supply outlet 31a and an upper return port 31b in the upper part thereof, and has a water supply port 31c, an outlet 31d and a lower return port 31e in the lower part thereof.

  The boiling circuit 5 includes a water heat exchanger 12, a tank 31, a pump 32, and a pipe connecting them in order. In the boiling circuit 5, the hot water in the tank 31 is taken out from the outlet 31 d by being driven by the pump 32, supplied to the water heat exchanger 12, heated in the water heat exchanger 12, and then returned to the upper part. It is returned into the tank 31 from the port 31b or the lower return port 31e.

  The boiling circuit 5 has a three-way valve 33 for communicating any one of the upper return port 31b and the lower return port 31e of the tank 31 with the hydrothermal exchanger 12. The three-way valve 33 is switched according to the temperature of the hot water heated by the water heat exchanger 12 (the temperature of the hot water). When the hot water temperature is low (for example, immediately after the start of the boiling operation), the three-way valve 33 is switched so that the hot water heated by the water heat exchanger 12 flows into the tank 31 from the lower return port 31e. When the temperature approaches the target hot water temperature, the hot water heated by the water heat exchanger 12 is switched so as to flow into the tank 31 from the upper return port 31b.

  Moreover, the rotation speed of the pump 32 can be changed. By reducing the rotation speed of the pump 32, the flow rate of the hot water returned to the tank 31 is reduced and the temperature thereof is increased. When the rotational speed of the pump 32 is increased, the reverse is true.

  The boiling circuit 5 detects the temperature of the warm water flowing into the water heat exchanger 12 (water temperature) and the temperature of the hot water heated by the water heat exchanger 12 (temperature of the hot water). A hot water thermistor 42.

  The hot water supply circuit 6 is configured to mix hot water discharged from the hot water supply outlet 31a of the tank 31 and water supplied from a water supply source in the mixing valve 34 and supply the mixed water to the hot water supply terminal. Further, the hot water supply circuit 6 is configured such that when hot water is discharged from the hot water supply outlet 31a, water from the water supply source is simultaneously supplied into the tank 31 from the water supply port 31c. Therefore, the temperature of the hot water in the tank 31 is high at the upper part and low at the lower part, except for the case where all of the hot water in the tank 31 is heated to a high temperature.

  A plurality of tank thermistors 43 are attached to the outer surface of the tank 31 side by side in the vertical direction. The tank thermistor 43 is for detecting the temperature of hot water in the tank 31. The temperature detected by the tank thermistor 43 is used for detecting how much hot water remains in the tank 31 (detecting the amount of remaining hot water).

[Configuration of control unit]
Next, the control part which controls the heat pump type water heater 1 will be described.
The control unit controls the compressor 11 of the refrigerant circuit 4, the motor operated valve 13, the fan 15, the pump 32 of the boiling circuit 5, and the three-way valve 33 to control the boiling operation and the defrost operation. In addition, when the hot water is discharged from the hot water supply terminal, the control unit controls the mixing valve 34 so that the hot water having the set temperature is supplied to the hot water supply terminal.

  The control unit determines whether or not to start the boiling operation based on the amount of remaining hot water in the tank 31 and the like. Further, the control unit sets the target hot water temperature based on the hot water supply temperature set by the remote controller or the like and the amount of hot water to be used, and sets the target discharge temperature based on the target hot water temperature. When starting the boiling operation, the control unit drives the compressor 11 and the fan 15 of the refrigerant circuit 4 and the pump 32 of the boiling circuit 5. During the boiling operation, the control unit controls the operation frequency of the compressor 11 and the electric motor so that the hot water temperature detected by the hot water thermistor 42 and the discharge temperature detected by the discharge thermistor 22 approach the target hot water temperature and the target discharge temperature, respectively. The opening degree of the valve 13, the rotational speed of the pump 32, and the rotational speed of the fan 15 are controlled. Further, during the boiling operation, the control unit switches the three-way valve 33 based on the tapping temperature.

  During the boiling operation, the control unit determines whether to start the defrost operation using a plurality of determination conditions (three conditions in the present embodiment), and performs the defrost operation based on any of the plurality of determination conditions. When it is determined to start, the defrost operation is started.

  FIG. 2 is a graph showing the relationship between the determination condition, the air heat exchange temperature and the elapsed time after startup. As shown in FIG. 2, in the first determination condition, the elapsed time t from the start of the boiling operation is t1 ≦ t <t2 (for example, t1 = 28 minutes, t2 = 90 minutes), and the air heat exchanger temperature T is T1 < When T ≦ T2 (for example, T1 = −27 ° C., T2 = −11 ° C.) and the outside air temperature, the flow rate of the pump 32, and the hot water temperature satisfy predetermined conditions, it is determined that the defrost operation is started. . Details of the first determination condition will be described later. The temperature T2 may be a fixed value or a value obtained by subtracting a predetermined value from the outside air temperature.

  In the second determination condition, it is determined that the defrost operation is started when the elapsed time t from the start of the boiling operation or the end of the previous defrost operation is t1 ≦ t <t2 and the air heat exchange temperature T is T ≦ T1. To do. In the third determination condition, it is determined that the defrost operation is started when the elapsed time t from the start of the boiling operation or the end of the previous defrost operation is t ≧ t2 or more and the air heat exchange temperature T is T ≦ T2. . By the second determination condition and the third determination condition, frost generated in the air heat exchanger 14 during the boiling operation can be removed.

Hereinafter, the first determination condition will be described with reference to the flowchart of FIG.
When starting the boiling operation (Step S1), the control unit determines whether or not the outside air temperature at the start detected by the outside air thermistor 23 is equal to or lower than a predetermined temperature A (Step S2). The temperature A is a temperature that may cause snowfall, and is, for example, 0 ° C. ± 2 to 3 ° C. When the outside air temperature is higher than the temperature A (step S2: NO), it is determined that the defrost operation is not started (step S3). On the other hand, when the outside air temperature is equal to or lower than the temperature A (step S2: YES), it is determined whether or not the elapsed time t since the start is equal to or longer than the time t1 (step S4).

  If the elapsed time t after activation is less than the time t1 (step S4: NO), this step S4 is repeated until the elapsed time t reaches t1, and the elapsed time t after activation becomes the time t. When it reaches (step S4: YES), it is determined whether or not the defrost operation is performed after the start (step S5).

  When the defrost operation is performed after the start (step S5: NO), it is determined that the defrost operation is not started (step S3). On the other hand, when the defrost operation is not performed after the start (step S5: YES), it is determined whether the elapsed time t after the start does not exceed the time t2 (step S6).

  When the elapsed time t since the start exceeds the time t2 (step S6: NO), it is determined that the defrost operation is not started (step S3). On the other hand, when the elapsed time t since the start exceeds the time t2 (step S6: YES), whether or not the air heat exchange temperature T detected by the heat exchange thermistor 21 is T1 <T ≦ T2. (Step S7).

  When the air heat exchange temperature T is equal to or lower than T1 or higher than T2 (step S7: NO), it is determined that the defrost operation is not started (step S3). On the other hand, when the air heat exchange temperature T is T1 <T ≦ T2 (step S7: YES), it is determined whether or not the flow rate of the pump 32 is equal to or lower than a predetermined flow rate F (step S8). The flow rate F is the minimum flow rate of the pump 32 or a value close thereto. Whether or not the flow rate of the pump 32 is equal to or less than the flow rate F may be determined by determining whether or not the rotation speed of the pump 32 is equal to or less than the rotation speed corresponding to the flow rate F.

  When the flow rate of the pump 32 is higher than the flow rate F (step S8: NO), the process returns to step S5. On the other hand, when the flow rate of the pump 32 is less than or equal to the flow rate F (step S8: YES), whether or not the temperature difference between the tapping temperature detected by the tapping thermistor 42 and the target tapping temperature is equal to or greater than a predetermined temperature difference ΔTw. Judgment is made (step S9). The temperature difference ΔTw is a positive value. The temperature difference between the tapping temperature and the target tapping temperature is a value obtained by subtracting the tapping temperature from the target tapping temperature.

  When the temperature difference between the tapping temperature and the target tapping temperature is smaller than ΔTw (step S9: NO), the process returns to step S5. On the other hand, when the temperature difference between the tapping temperature and the target tapping temperature is equal to or greater than ΔTw (step S9: YES), the flow rate of the pump 32 is equal to or less than the flow rate F, and the temperature difference between the tapping temperature and the target tapping temperature is ΔTw. It is determined whether or not the above state continues for a predetermined time ta (for example, 3 to 15 minutes) (step S10).

  When the duration of the state where the flow rate of the pump 32 is not more than the flow rate F and the temperature difference between the tapping temperature and the target tapping temperature is not less than ΔTw is less than ta (step S10: NO), the process proceeds to step S5. Returning, when the duration has reached ta (step S10: YES), it is determined to start the defrost operation (step S11).

  When it is determined that the defrost operation is started under any one of a plurality of determination conditions and the defrost operation is started, the control unit stops the pump 32 to stop the circulation of the hot water in the boiling circuit 5, and The valve 13 is fully opened to supply a high-temperature refrigerant to the air heat exchanger 14. Further, the control unit stops the fan 15 during the defrost operation and sets the operation frequency of the compressor 11 to a low frequency. When the defrost operation is performed and the air heat exchange temperature rises to a predetermined temperature, the control unit ends the defrost operation and restarts the boiling operation.

[Characteristics of Heat Pump Type Water Heater of First Embodiment]
The heat pump type water heater 1 of the present embodiment has the following characteristics.

  In this heat pump type hot water supply apparatus 1, the defrosting operation is performed according to the first determination condition when the tapping temperature is lower than the target tapping temperature by ΔTw or more despite the control of increasing the tapping temperature by reducing the pump flow rate. Start. Accordingly, when frost or snow is generated in the air heat exchanger 14 before starting and the boiling capacity at the time of starting is low, the defrosting operation can be started. Therefore, the hot water temperature remains at the target hot water temperature while the boiling capacity remains low. It is possible to prevent the operation that does not reach the condition from continuing for a long time.

  Even if frost or snow has occurred in the air heat exchanger 14 before startup, frost or snow is removed if the defrost operation is performed even once after startup. Steps S6 to S10 of the first determination condition are for determining whether or not frost or snow is generated in the air heat exchanger 14 at the time of startup, and therefore, the determination by steps S6 to S10 is performed after the defrost operation. There is no need to do it. Therefore, only when the defrosting operation is not performed after being started (step S5: YES), unnecessary determinations can be eliminated and erroneous determinations can be prevented by performing the determinations of steps S6 to S10. The erroneous determination is to determine that the defrost operation is started when the frost or snow is hardly generated in the air heat exchanger 14 and the defrost operation is unnecessary.

  When the outside air temperature at the time of start-up is high, frost or snow is not generated in the air heat exchanger 14 at the time of start-up, so it is not necessary to perform the determinations in steps S4 to S10 of the first determination condition. Therefore, by performing the determinations in steps S4 to S10 only when the outside air temperature is equal to or lower than the temperature A at which snow is likely to be deposited, unnecessary determinations can be eliminated and erroneous determinations can be prevented.

  When the air heat exchanger temperature T is high, no frost or snow has occurred on the air heat exchanger 14, and therefore, it is not necessary to perform the determinations in steps S8 to S10 only when the air heat exchanger temperature is equal to or lower than the temperature T2. This makes it possible to eliminate erroneous judgments and prevent erroneous judgments.

  Further, even if frost or snow is not generated in the air heat exchanger 14 at the time of startup, the air heat exchange temperature, the hot water temperature, and the discharge temperature may be low immediately after the startup. Therefore, erroneous determination can be prevented by performing the determinations in steps S4 to S10 after the predetermined time t1 has elapsed after the start and the air heat exchange temperature T, the hot water temperature, and the discharge temperature are stabilized.

Second Embodiment
Next, a second embodiment of the present invention will be described. However, about the thing which has the structure similar to the said 1st Embodiment, the description is abbreviate | omitted suitably using the same code | symbol.
The heat pump type water heater of the present embodiment is different from the first embodiment in part of the first determination condition, and the other configuration is the same as that of the first embodiment.

  The first determination condition of the present embodiment is that the elapsed time t from the start of the boiling operation is t1 ≦ t <t2, the air heat exchange temperature T is T1 <T ≦ T2, and the outside air temperature, the electric valve When the flow rate of 13 and the discharge temperature satisfy the predetermined conditions, it is determined that the defrost operation is started.

Hereinafter, the first determination condition will be described with reference to the flowchart of FIG.
Steps S21 to S27 are the same as steps S1 to S7 of the first determination condition of the first embodiment. When the air heat exchange temperature T is T1 <T ≦ T2 (step S27: YES), it is determined whether or not the opening degree of the motor-operated valve 13 is equal to or less than a predetermined opening degree D (step S28). The opening degree D is the minimum opening degree of the motor-operated valve 13 or a value close thereto. The determination as to whether the motor-operated valve opening is equal to or less than the opening D may be made by determining whether the flow rate in the motor-operated valve 13 is equal to or less than the flow rate corresponding to the opening D.

  When the opening degree of the motor-operated valve 13 is larger than the opening degree D (step S28: NO), the process returns to step S25. On the other hand, when the opening degree of the motor-operated valve 13 is not more than the opening degree D (step S28: YES), the temperature difference between the discharge temperature detected by the discharge thermistor 22 and the target discharge temperature is not less than a predetermined temperature difference ΔTr. Whether or not (step S29). The temperature difference ΔTr is a positive value, and the temperature difference between the discharge temperature and the target discharge temperature is a value obtained by subtracting the discharge temperature from the target discharge temperature.

  When the temperature difference between the discharge temperature and the target discharge temperature is smaller than ΔTr (step S29: NO), the process returns to step S25. On the other hand, when the temperature difference between the discharge temperature and the target discharge temperature is equal to or larger than ΔTr (step S29: YES), the opening degree of the motor-operated valve 13 is not more than the opening degree D and the temperature between the discharge temperature and the target discharge temperature. It is determined whether or not the state where the difference is equal to or larger than ΔTr continues for a predetermined time tb (eg, 3 to 15 minutes) (step S30).

  When the duration of the state in which the opening degree of the motor-operated valve 13 is not more than the opening degree D and the temperature difference between the discharge temperature and the target discharge temperature is equal to or greater than ΔTr is less than tb (step S30: NO), Returning to step S25, when the duration has reached the time tb (step S30: YES), it is determined to start the defrost operation (step S31).

  The control of the defrost operation is the same as in the first embodiment.

[Characteristics of Heat Pump Water Heater of Second Embodiment]
The heat pump type hot water heater of the present embodiment has the following features as features different from the first embodiment.

  In this heat pump type water heater, the first determination condition is met when the discharge temperature is lower than the target discharge temperature by a temperature ΔTr or more despite the control of increasing the discharge temperature by reducing the opening of the motor operated valve 13. To start defrosting. Therefore, when frost or snow is generated in the air heat exchanger 14 before starting and the boiling capacity at the time of starting is low, the defrosting operation can be started, so that the discharge temperature and the tapping temperature remain low while the boiling capacity remains low. It is possible to prevent the operation not reaching the target temperature from continuing for a long time.

<Third Embodiment>
Next, a third embodiment of the present invention will be described. However, about the thing which has the structure similar to the said 1st Embodiment, the description is abbreviate | omitted suitably using the same code | symbol.
The heat pump type water heater of the present embodiment is different from the first embodiment in part of the first determination condition, and the other configuration is the same as that of the first embodiment.

  The first determination condition of this embodiment is that the elapsed time t from the start of the boiling operation is t1 ≦ t <t2, the air heat exchange temperature T is T1 <T ≦ T2, the outside air temperature, the pump 32 The defrosting operation is determined to start when the flow rate of the motor, the flow rate of the motor operated valve 13, the hot water temperature and the discharge temperature satisfy the predetermined conditions.

Hereinafter, the first determination condition will be described with reference to the flowchart of FIG.
Steps S41 to S47 are the same as steps S1 to S7 of the first determination condition of the first embodiment. When the air heat exchange temperature T is T1 <T ≦ T2 (step S47: YES), it is determined whether the flow rate of the pump 32 is equal to or lower than the flow rate F (step S48), and the opening degree of the motor-operated valve 13 is determined. It is determined whether or not the opening degree is equal to or less than the opening degree D (step S53).

  When the flow rate of the pump 32 is higher than the flow rate F (step S48: NO), the process returns to step S45, and when the flow rate of the pump 32 is less than the flow rate F (step S48: YES), the tapping temperature and the target tapping temperature. It is determined whether or not the temperature difference between is ΔTw or more (step S49). When the temperature difference between the tapping temperature and the target tapping temperature is smaller than ΔTw (step S49: NO), the process returns to step S45. On the other hand, when the temperature difference is equal to or greater than ΔTw (step S49: YES), the state in which the flow rate of the pump 32 is equal to or less than the flow rate F and the temperature difference between the tapping temperature and the target tapping temperature is equal to or greater than ΔTw. It is determined whether or not to continue (step S50).

  When the duration of the state in which the flow rate of the pump 32 is equal to or less than the flow rate F and the temperature difference between the tapping temperature and the target tapping temperature is equal to or greater than ΔTw is less than time ta (step S50: NO), step Returning to S45, if the duration has reached the time ta (step S50: YES), a first snowfall determination is performed (step S51).

  When the opening degree of the motor-operated valve 13 is larger than the opening degree D (step S53: NO), the process returns to step S45, and when the opening degree of the motor-operated valve 13 is less than the opening degree D (step S53: YES). ), It is determined whether or not the temperature difference between the discharge temperature and the target discharge temperature is equal to or greater than ΔTr (step S54). When the temperature difference between the discharge temperature and the target discharge temperature is smaller than ΔTr (step S54: NO), the process returns to step S45, and when the temperature difference between the discharge temperature and the target discharge temperature is equal to or greater than ΔTr (step S54). : YES), it is determined whether or not the state where the opening degree of the motor-operated valve 13 is not more than the opening degree D and the temperature difference between the discharge temperature and the target discharge temperature is ΔTr or more continues for the time tb (step S55). .

  When the duration of the state where the opening degree of the motor-operated valve 13 is not more than the opening degree D and the temperature difference between the discharge temperature and the target discharge temperature is not less than ΔTr is less than the time tb (step S55: NO) ), The process returns to step S45, and when the duration has reached the time tb (step S55: YES), the second snowfall determination is performed (step S56).

  Then, when both the first snowfall determination and the second snowfall determination are performed (step S52: YES, step S57: YES), it is determined to start the defrost operation (step S58). When the second snowfall judgment is not made and only the first snowfall judgment is made (step S52: NO), the process returns to step S50, the first snowfall judgment is not made, and only the second snowfall judgment is made. If (step S57: NO), the process returns to step S55.

  The control of the defrost operation is the same as in the first embodiment.

[Characteristics of the heat pump type water heater of the third embodiment]
The heat pump type hot water heater of the present embodiment has the following features as features different from the first embodiment.

  In this heat pump type hot water supply apparatus, the hot water temperature is lower than the target hot water temperature by ΔTw or more, although the pump flow rate and the motor valve opening are reduced to increase the hot water temperature and the discharge temperature. When the discharge temperature is lower than the target discharge temperature by a temperature ΔTr or more, the defrost operation is started based on the first determination condition. Therefore, when frost or snow is generated in the air heat exchanger 14 before starting and the boiling capacity at the time of starting is low, the defrosting operation can be started, so that the tapping temperature and the discharge temperature remain low while the boiling capacity remains low. It is possible to prevent the operation not reaching the target temperature from continuing for a long time.

  Further, erroneous determination can be prevented as compared with the case where the pump flow rate and the hot water temperature are not used as the first determination condition, or when the motor-operated valve opening degree and the discharge temperature are not used.

  As mentioned above, although embodiment of this invention was described, it should be thought that the specific structure of this invention is not limited to the said embodiment. The scope of the present invention is shown not only by the description of the above-described embodiment but also by the scope of claims for patent, and further includes meanings equivalent to the scope of claims for patent and all modifications within the scope.

  When both the first determination condition of the first embodiment and the first determination condition of the second embodiment are used as the defrost operation determination conditions, and the frost operation start determination is made in any of a plurality of determination conditions. The defrosting operation may be started. According to this configuration, the defrosting operation can be started more reliably when snow or frosting occurs than in the first to third embodiments.

  In the first to third embodiments, the defrost operation is performed by supplying the high-temperature refrigerant to the air heat exchanger 14 by fully opening the motor-operated valve 13, but the method of the defrost operation is not limited to this. For example, when a bypass pipe that connects the downstream pipe of the compressor 11 and the upstream pipe of the air heat exchanger 14 is provided, and a defrosting operation is performed by providing an open / close valve in the bypass pipe. Alternatively, the on-off valve may be opened to supply the high-temperature refrigerant discharged from the compressor 11 to the air heat exchanger 14 without passing through the water heat exchanger 12.

  If the present invention is used, it is possible to prevent the heat pump hot water supply apparatus from being operated for a long time while the boiling capacity remains low and the hot water temperature does not reach the target hot water temperature.

DESCRIPTION OF SYMBOLS 1 Heat pump type hot water supply machine 2 Heat pump unit 3 Hot water supply unit 4 Refrigerant circuit 5 Boiling circuit 6 Hot water supply circuit 11 Compressor 12 Water heat exchanger 13 Electric valve 14 Air heat exchanger 15 Fan 31 Tank 32 Pump

Claims (7)

A compressor, a water heat exchanger for heating hot water, a refrigerant circuit in which an electric valve and an air heat exchanger are connected in order, and supplying the water heat exchanger, the tank, and hot water from the tank to the water heat exchanger A heat pump type water heater provided with a boiling circuit connected to the pump
The start determination of the defrost operation continues for a predetermined pump determination time in which the flow rate in the pump is equal to or less than a predetermined pump flow rate and the temperature difference between the tapping temperature and the target tapping temperature is equal to or greater than the predetermined tapping temperature difference. A heat pump type water heater, which is performed when   The defrost operation start determination is that the opening degree of the motor-operated valve is equal to or less than a predetermined motor-operated valve opening degree, and the temperature difference between the discharge temperature of the compressor and the target discharge temperature corresponding to the target hot water temperature is a predetermined discharge temperature. The heat pump type hot water heater according to claim 1, which is performed when a state equal to or greater than the difference is continued for a predetermined motor-operated valve determination time. A compressor, a water heat exchanger for heating hot water, a refrigerant circuit in which an electric valve and an air heat exchanger are connected in order, and supplying the water heat exchanger, the tank, and hot water from the tank to the water heat exchanger A heat pump type water heater provided with a boiling circuit connected to the pump
The defrost operation start determination is that the opening degree of the motor-operated valve is equal to or less than a predetermined motor-operated valve opening degree, and the temperature difference between the discharge temperature of the compressor and the target discharge temperature corresponding to the target hot water temperature is a predetermined discharge temperature. A heat pump type hot water heater, which is performed when a state equal to or greater than the difference is continued for a predetermined motor-operated valve determination time. A compressor, a water heat exchanger for heating hot water, a refrigerant circuit in which an electric valve and an air heat exchanger are connected in order, and supplying the water heat exchanger, the tank, and hot water from the tank to the water heat exchanger A heat pump type water heater provided with a boiling circuit connected to the pump
The start determination of the defrost operation continues for a predetermined pump determination time in which the flow rate in the pump is equal to or less than a predetermined pump flow rate and the temperature difference between the tapping temperature and the target tapping temperature is equal to or greater than the predetermined tapping temperature difference. And the temperature difference between the discharge temperature of the compressor and the target discharge temperature corresponding to the target hot water temperature is greater than or equal to the predetermined discharge temperature difference. A heat pump type hot water heater, which is performed when the state continues for a predetermined electric valve determination time.   The heat pump type water heater according to any one of claims 1 to 4, wherein the start determination of the defrost operation is performed when the defrost operation has never been performed after being activated.   The heat pump type hot water heater according to any one of claims 1 to 5, wherein the start determination of the defrost operation is performed when the outside air temperature is started at a predetermined temperature or lower.   2. The start determination of the defrost operation is performed when the temperature of the air heat exchanger is equal to or lower than a predetermined heat exchanger temperature and a predetermined operation time is continued after startup. The heat pump type hot water heater according to any one of -6.

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