JP2011102678A - Heat pump device - Google Patents

Abstract

A heat pump device capable of releasing defrosting operation at an optimal timing is provided.
A refrigerant circuit having a compressor 1, a condenser 2, an electric expansion valve EV and an evaporator 4, a discharge pipe temperature sensor T1 for detecting a discharge pipe temperature of the compressor 1, and the electric expansion valve EV are fully opened. And a control device 10 that performs forward cycle defrosting operation. The control device 10 includes a defrost operation canceling unit 10a that cancels the normal cycle defrost operation based on the discharge pipe temperature detected by the discharge pipe temperature sensor T1.
[Selection] Figure 1

Description

  The present invention relates to a heat pump device.

  Conventionally, as a heat pump device, when the temperature of the evaporator reaches a predetermined temperature during the defrosting operation, there is a heat pump device that ends the defrosting operation and returns to the normal operation (for example, Japanese Patent Laid-Open No. 4-344085). See Patent Document 1)).

  However, in the heat pump device, the predetermined temperature is set higher than the temperature of the evaporator when the frost of the evaporator is completely melted so that the frost is not melted. For this reason, even after the evaporator frost has completely melted, the defrost operation continues, and the stop time of the normal operation becomes longer. Thus, in the said heat pump apparatus, it cannot judge reliably that defrosting of the evaporator was completed, and there exists a problem that a defrost driving | operation cannot be cancelled | released at the optimal timing.

  In the above heat pump device, the temperature sensor for detecting the temperature of the evaporator is provided at the position of the evaporator suitable for controlling the refrigerant circuit, and the optimum evaporator position (for the evaporator) for defrosting. It is not easy to determine that the evaporator frost has completely melted based on the temperature of the evaporator detected by such a temperature sensor.

JP-A-4-344085

  Then, the subject of this invention is providing the heat pump apparatus which can cancel | release defrost driving | operation at the optimal timing.

In order to solve the above problems, the heat pump device of the present invention is
A refrigerant circuit having a compressor, a condenser, an electric expansion valve, and an evaporator;
A discharge pipe temperature sensor for detecting the discharge pipe temperature of the compressor;
A controller that performs full cycle defrost operation by fully opening the electric expansion valve;
The control device includes a defrost operation canceling unit that cancels the normal cycle defrost operation based on the discharge pipe temperature detected by the discharge pipe temperature sensor.

  According to the above configuration, when the evaporator is frosted in the normal operation of the normal cycle in which the refrigerant flows in the order of the compressor, the condenser, the electric expansion valve, and the evaporator, the control device operates the compressor with the electric expansion valve fully opened. By doing so, a positive cycle defrost operation is performed. In this forward cycle defrost operation, the heat of the high-temperature refrigerant discharged from the compressor is consumed for defrosting by the evaporator, so the discharge pipe temperature of the compressor gradually decreases. Then, when all the frost adhering to the evaporator is melted by this defrost operation and heat is not consumed in the evaporator, the discharge pipe temperature of the compressor starts to rise. Accordingly, the defrost operation canceling unit that cancels the normal cycle defrost operation based on the discharge pipe temperature detected by the discharge pipe temperature sensor uses the discharge pipe temperature characteristic at the time of the defrost operation to optimize the defrost operation. It becomes possible to cancel with.

Moreover, in the heat pump device of one embodiment,
An evaporator temperature sensor for detecting the temperature of the evaporator;
The control device includes an evaporator temperature determination unit that determines whether or not the evaporator temperature detected by the evaporator temperature sensor is equal to or higher than a defrost release temperature,
When the evaporator temperature determination unit determines that the evaporator temperature detected by the evaporator temperature sensor is equal to or higher than the defrost release temperature during the positive cycle defrost operation, the defrost operation release unit Cancel driving.

  According to the above embodiment, during the positive cycle defrost operation, when the evaporator temperature determination unit determines that the evaporator temperature detected by the evaporator temperature sensor is equal to or higher than the defrost release temperature, the defrost operation release unit causes the positive cycle defrost operation. By canceling the operation, the defrost operation can be reliably canceled even if the defrost release determination using the discharge pipe temperature characteristic during the defrost operation is delayed.

Moreover, in the heat pump device of one embodiment,
The controller determines whether or not the discharge pipe temperature detected by the discharge pipe temperature sensor has changed from a decrease after the start of the positive cycle defrost operation to an increase during the positive cycle defrost operation. While having a tube temperature determination unit,
The defrost operation canceling unit is configured such that the discharge pipe temperature determination unit is configured to increase the discharge pipe temperature detected by the discharge pipe temperature sensor from a drop after the start of the positive cycle defrost operation during the positive cycle defrost operation. If it is determined that the change has been made, the normal cycle defrost operation is canceled.

  According to the above embodiment, when the discharge pipe temperature determination unit determines that the discharge pipe temperature detected by the discharge pipe temperature sensor has changed from a drop after the start of the positive cycle defrost operation to an increase during the positive cycle defrost operation. By releasing the normal cycle defrost operation by the defrost operation release unit, the defrost operation can be reliably released at an optimal timing.

Moreover, in the heat pump device of one embodiment,
The control device determines whether or not the discharge pipe temperature detected by the discharge pipe temperature sensor has increased by a predetermined temperature from the lowest temperature during the positive cycle defrost operation during the positive cycle defrost operation. While having a temperature determination unit,
The defrost operation canceling unit is configured such that the discharge pipe temperature determining unit detects the discharge pipe temperature detected by the discharge pipe temperature sensor during the positive cycle defrost operation from the lowest temperature during the positive cycle defrost operation. If it is determined that the temperature has risen, the normal cycle defrost operation is canceled.

  According to the above embodiment, when the discharge pipe temperature determination unit determines that the discharge pipe temperature detected by the discharge pipe temperature sensor has increased by a predetermined temperature from the lowest temperature during the positive cycle defrost operation during the positive cycle defrost operation, By canceling the normal cycle defrost operation by the defrost operation canceling unit, the defrost operation can be reliably canceled at the optimum timing.

  As is clear from the above, according to the heat pump device of the present invention, it is possible to realize a heat pump device that can release the defrost operation at an optimal timing.

FIG. 1 is a circuit diagram of a heat pump apparatus according to a first embodiment of the present invention. FIG. 2 is a graph showing changes in the discharge pipe temperature, the amount of frost, and the evaporator temperature during the defrost operation of the heat pump device. FIG. 3 is a flowchart for explaining the operation during the defrost operation of the control device of the heat pump device. FIG. 4 shows changes in the discharge pipe temperature of the compressor, the operating frequency of the compressor, the target opening of the electric expansion valve, the air heat exchanger temperature, the intake temperature of the compressor, and the outside air temperature during the defrost operation of the heat pump device. FIG. FIG. 5 is a diagram showing the discharge pipe temperature of the compressor shown in FIG. 4 and the suction temperature of the compressor. FIG. 6 is a diagram showing changes in the discharge pipe temperature of the compressor, the operating frequency of the compressor, the target opening of the electric expansion valve, the evaporator temperature, the intake temperature of the compressor, and the outside air temperature during the defrost operation of the heat pump device. is there. FIG. 7 is a diagram showing the discharge pipe temperature of the compressor shown in FIG. 6 and the suction temperature of the compressor. FIG. 8 is a flowchart for explaining the operation during the defrost operation of the control device for the heat pump apparatus according to the second embodiment of the present invention. FIG. 9 is a flowchart for explaining the operation during the defrosting operation of the control device of the heat pump apparatus according to the third embodiment of the present invention.

  Hereinafter, the heat pump device of the present invention will be described in detail with reference to embodiments shown in the drawings.

[First Embodiment]
FIG. 1 shows a circuit diagram of a heat pump apparatus according to a first embodiment of the present invention. This heat pump device is used in a hot water storage type hot water heater.

As shown in FIG. 1, the heat pump device according to the first embodiment includes a compressor 1 and a condenser (water heat exchange) having one end (primary side) connected to the discharge side of the compressor 1 via a pipe L1. 2), a gas heat exchanger 3 having one end (high pressure side) connected to the other end (primary side) of the condenser 2 via a pipe L2, and the other end (high pressure side) of the gas heat exchanger 3 ), One end of which is connected to the other end of the electric expansion valve EV via a pipe L4 and the other end of which is connected to the gas heat exchanger 3 via a pipe L5. Is connected to one end (low pressure side) of the evaporator (air heat exchanger) 4 and the other end of the gas heat exchanger 3 on the low pressure side via the pipe L6, and the other end is connected to the pipe L7. And an accumulator 5 connected to the suction side of the compressor 1 and a blower fan 6 for supplying outside air to the evaporator 4. The compressor 1, the condenser 2, the electric expansion valve EV, and the evaporator 4 constitute a refrigerant circuit. The heat pump device uses a CO ₂ refrigerant that has a small global warming potential and does not destroy ozone.

  Further, on the discharge side of the compressor 1, a discharge pipe temperature sensor T1 for detecting the discharge temperature and a pressure sensor HPS for detecting the discharge pressure are arranged. Further, an evaporator temperature sensor T2 for detecting the evaporator temperature is arranged in the evaporator 4, and an outside air temperature sensor T3 for detecting the outside air temperature is arranged in the vicinity of the evaporator 4.

  In addition, one end of the pipe L11 is connected to one end (secondary side) of the condenser 2, and the other end of the pipe L11 is connected to a hot water storage tank (not shown). On the other hand, one end of the pipe L12 is connected to the other end (secondary side) of the condenser 2, and the other end of the pipe L12 is connected to the hot water storage tank. An incoming water temperature sensor T4 is arranged in the pipe L11, and a tapping temperature sensor T5 is arranged in the pipe L12.

  The heat pump device includes a control device 10 including a microcomputer and an input / output circuit. The control device 10 includes a defrost operation canceling unit 10a that cancels the normal cycle defrost operation, an evaporator temperature determining unit 10b that determines the evaporator temperature, and a discharge pipe temperature determining unit 10c that determines the discharge pipe temperature. Based on detection signals from the discharge pipe temperature sensor T1, the evaporator temperature sensor T2, the outside air temperature sensor T3, and the pressure sensor HPS, the control device 10 controls the compressor 1, the electric expansion valve EV, the blower fan 6, and the like. .

  When the water in the hot water storage tank is boiled using the heat pump device having the above configuration, the compressor 1 of the heat pump device is driven and the operation of the blower fan 6 is started. Then, a boiling circulation pump (not shown) for circulating the water in the hot water storage tank through the condenser 2 is driven. Then, the high-pressure gas refrigerant discharged from the compressor 1 becomes a liquid refrigerant by radiating and condensing in the condenser 2, and then the low-pressure refrigerant decompressed by the electric expansion valve EV is discharged from the outside air by the evaporator 4. It absorbs heat and evaporates. Then, the low-pressure gas refrigerant evaporated in the evaporator 4 returns to the suction side of the compressor 1. At this time, the water that has flowed into the secondary side of the condenser 2 from the lower part of the hot water storage tank through the pipe L11 by the boiling circulation pump is heated by the condenser 2 to become hot water close to 90 ° C., and passes through the pipe L12. Return to the top of the hot water storage tank 21. In this way, the water in the hot water storage tank is boiled by circulating the water in the hot water storage tank through the circulating pump for boiling and the condenser 2.

  Here, the gas heat exchanger 3 suppresses an excessive increase in high pressure by performing heat exchange between the high-pressure and high-temperature refrigerant exiting from the condenser 2 and the low-pressure and low-temperature refrigerant exiting from the evaporator 4.

  When the boiling operation is continued or intermittently repeated, frost forms on the evaporator 4 depending on conditions such as the outside air temperature. In this heat pump device, frost adhering to the evaporator 4 is melted by a positive cycle defrost operation in which the opening of the electric expansion valve EV is fully opened.

  In the normal cycle defrost operation (hereinafter referred to as defrost operation), the discharge pipe temperature of the compressor 1, the amount of frost in the evaporator 4 and the evaporator temperature change as shown in FIG. As time elapses from the start of the defrost operation, as shown in FIG. 2, the amount of frost gradually decreases and the discharge pipe temperature of the compressor 1 gradually decreases, but the discharge pipe temperature is zero. The slope becomes gentle before it becomes low, and after reaching a minimum temperature near the amount of frost reaching zero, it begins to rise.

  In the conventional heat pump device, as shown in FIG. 2, the evaporator temperature that gradually increases with the passage of time from the start of the defrost operation is compared with the judgment value, and the defrost operation is performed when the evaporator temperature exceeds the judgment value. Was released.

  On the other hand, in the first embodiment, during the defrost operation, the evaporator temperature detected by the evaporator temperature sensor T2 by the evaporator temperature determination unit 10b is the defrost release temperature X ° C. (7 ° C. in this embodiment). The discharge pipe temperature determination unit 10c determines that the discharge pipe temperature detected by the discharge pipe temperature sensor T1 has changed from a decrease after the start of the defrost operation to an increase during the defrost operation. Then, the defrost operation is canceled by the defrost operation canceling unit 10a. By doing so, the defrosting operation can be surely released at an optimal timing.

  Further, during the defrost operation, when the evaporator temperature determination unit 10b determines that the evaporator temperature detected by the evaporator temperature sensor T2 is equal to or higher than the defrost release temperature X ° C., the defrost operation release unit 10a cancels the defrost operation. Therefore, even if the defrost release determination using the discharge pipe temperature characteristic during the defrost operation is delayed, the defrost operation can be reliably released.

  FIG. 3 shows a flowchart for explaining the operation of the control device 10 of the heat pump device during the defrost operation.

  First, when the process starts, the defrost operation is started in step S1. That is, during the boiling operation, the boiling circulation pump that circulates the water in the hot water storage tank through the condenser 2 is stopped, the opening of the electric expansion valve EV is fully opened, and the operating frequency of the compressor 1 To the frequency during defrost operation.

  Next, the process proceeds to step S2, and the evaporator temperature is detected by the evaporator temperature sensor T2.

  Next, it progresses to step S3 and it is determined by the evaporator temperature determination part 10b whether an evaporator temperature is more than defrost cancellation | release temperature X degreeC. When the evaporator temperature determination unit 10b determines in step S3 that the evaporator temperature is equal to or higher than the defrost release temperature X ° C., the process proceeds to step S6, the defrost operation is released by the defrost operation release unit 10a, and this process is terminated. To do.

  On the other hand, if the evaporator temperature determination unit 10b determines in step S3 that the evaporator temperature is lower than the defrost release temperature X ° C., the process proceeds to step S4, and the discharge pipe temperature sensor T1 detects the discharge pipe temperature.

  Next, it progresses to step S5 and it is determined by the discharge pipe temperature determination part 10c whether the discharge pipe temperature changed from the fall to the raise. That is, it is determined whether or not the discharge pipe temperature detected by the discharge pipe temperature sensor T1 has changed from a decrease after the start of the defrost operation to an increase.

  When the discharge pipe temperature determination unit 10c determines in step S5 that the discharge pipe temperature has changed from a decrease to an increase, the process proceeds to step S6, where the defrost operation is canceled by the defrost operation cancellation unit 10a, and this process ends. Here, before proceeding from step S5 to step S6, after waiting for a predetermined time (in this embodiment, 30 seconds), the process may proceed to step S6 so that the release of the defrost operation is delayed to give a margin.

  On the other hand, if the discharge pipe temperature determination unit 10c determines in step S5 that the discharge pipe temperature has not changed from a decrease to an increase, the process returns to step S2.

  FIG. 4 shows changes in the discharge pipe temperature of the compressor 1, the operating frequency of the compressor 1, the target opening of the electric expansion valve EV, the evaporator temperature, the intake temperature of the compressor 1, and the outside air temperature during the defrost operation of the heat pump device. FIG. 5 shows only the discharge pipe temperature of the compressor 1 and the suction temperature of the compressor 1 shown in FIG. 4 and 5 show a case where the operating frequency of the compressor 1 during normal operation before and after the defrost operation is lower than that during the defrost operation. 4 and 5, the horizontal axis represents the elapsed time [arbitrary scale], and the horizontal axis represents the operating frequency [arbitrary scale], each part temperature [arbitrary scale], and the opening.

  As shown in FIG. 4, when the normal operation is temporarily stopped and the defrost operation is started, the target opening degree of the electric expansion valve EV is fully opened, and the operation frequency of the compressor 1 is made higher than that during the normal operation. As a result, the discharge pipe temperature of the compressor 1 gradually decreases, and the evaporator temperature and the suction temperature of the compressor 1 rise. Then, when the frost in the evaporator 4 is completely melted, the discharge pipe temperature starts to increase from the decrease.

  In this defrosting operation, the heat of the high-temperature refrigerant discharged from the compressor 1 is consumed by the evaporator 4 for defrosting, so the discharge pipe temperature of the compressor 1 gradually decreases, and frost attached to the evaporator 4 is removed. When all is melted and heat is no longer consumed in the evaporator 4, the discharge pipe temperature of the compressor 1 starts to rise. Thus, in FIG. 4, during the defrost operation, the evaporator temperature determination unit 10b determines that the evaporator temperature detected by the evaporator temperature sensor T2 is lower than the defrost release temperature, and the discharge pipe temperature sensor T1. When the discharge pipe temperature determination unit 10c determines that the discharge pipe temperature detected by the above has changed from a decrease after the start of the defrost operation to an increase, the defrost operation release unit 10a releases the defrost operation. After the defrost operation is released, the compressor 1 returns to the normal operation frequency, and the electric expansion valve EV also returns to the normal operation opening, whereby the discharge pipe temperature rises and the evaporator temperature of the evaporator 4 rises. Stop.

  6 shows the discharge pipe temperature of the compressor 1 during the defrosting operation of the heat pump device, the operating frequency of the compressor 1, the target opening of the electric expansion valve EV, the evaporator temperature, the intake temperature of the compressor 1, and the outside air temperature. FIG. 7 shows only the discharge pipe temperature of the compressor 1 and the suction temperature of the compressor 1 shown in FIG. 6 and 7 show a case where the operating frequency of the compressor 1 during the normal operation before and after the defrost operation is higher than that during the defrost operation. 6 and 7, the horizontal axis represents the elapsed time [arbitrary scale], and the horizontal axis represents the operating frequency [arbitrary scale] of the compressor 1, the temperature [arbitrary scale] and the opening of each part.

  As shown in FIGS. 5 and 7, in the defrosting operation, while the frost in the evaporator 4 is melted, the discharge pipe temperature of the compressor 1 decreases while the suction temperature of the compressor 1 increases. When the frost in the evaporator 4 is completely melted, heat is not consumed in the evaporator 4 and the discharge pipe temperature starts to rise from the fall, but the suction temperature of the compressor 1 continues to rise. Of the compressor 1 affected by the condenser 2, the gas heat exchanger 3 and the evaporator 4 with respect to the refrigerant temperature immediately exiting the compressor 1, that is, the discharge pipe temperature having the highest temperature in the refrigerant circuit. At the suction temperature, a displacement point indicating that the defrosting of the evaporator 4 has been completed does not appear. Thus, the characteristics during defrost operation are completely different between the discharge pipe temperature and the suction temperature.

  In the first embodiment, during the defrost operation, the evaporator temperature determination unit 10b determines that the evaporator temperature detected by the evaporator temperature sensor T2 is lower than the defrost release temperature, and the discharge pipe temperature sensor. When the discharge pipe temperature determination unit 10c determines that the discharge pipe temperature detected by T1 has changed from a decrease after the start of the defrost operation to an increase, the defrost operation is released by the defrost operation release unit 10a. The determination may not be performed, and the defrost operation may be canceled by a change in the discharge pipe temperature (from rising to rising).

[Second Embodiment]
FIG. 8 is a flowchart for explaining the operation during the defrosting operation of the control device 10 of the heat pump apparatus according to the second embodiment of the present invention. The heat pump device of the second embodiment has the same configuration as that of the heat pump device of the first embodiment except for the control device 10, and uses FIG.

  The flowchart of FIG. 8 of the second embodiment differs from the flowchart of FIG. 3 of the first embodiment in that step S5 of FIG. 3 is replaced with step S10.

  Hereinafter, operations different from those of the control device 10 of the first embodiment will be mainly described.

  If the evaporator temperature determination unit 10b determines in step S3 that the evaporator temperature is lower than the defrost release temperature X ° C., the process proceeds to step S4, and the discharge pipe temperature sensor T1 detects the discharge pipe temperature.

  Next, it progresses to step S10, and it is determined by the discharge pipe temperature determination part 10c whether the discharge pipe temperature rose predetermined temperature A degreeC from minimum temperature. That is, it is determined whether or not the discharge pipe temperature detected by the discharge pipe temperature sensor T1 has increased by a predetermined temperature A ° C. from the lowest temperature after the start of the defrost operation.

  When the discharge pipe temperature determination unit 10c determines in step S10 that the discharge pipe temperature has increased from the lowest temperature by a predetermined temperature A ° C, the process proceeds to step S6, and the defrost operation release unit 10a releases the defrost operation.

  On the other hand, when the discharge pipe temperature determination unit 10c determines in step S10 that the discharge pipe temperature has not increased from the lowest temperature by the predetermined temperature A ° C., the process returns to step S2.

  Thus, in the heat pump device of the second embodiment, the evaporator temperature determination unit 10b determines that the evaporator temperature detected by the evaporator temperature sensor T2 is lower than the defrost release temperature X ° C. during the defrost operation. When the discharge pipe temperature determination unit 10c determines that the discharge pipe temperature detected by the discharge pipe temperature sensor T1 has increased by a predetermined temperature A ° C from the lowest temperature during the defrost operation, the defrost operation release unit 10a performs the defrost operation. By canceling, by doing so, the defrosting operation can be reliably canceled at an optimal timing.

  Further, during the defrost operation, when the evaporator temperature determination unit 10b determines that the evaporator temperature detected by the evaporator temperature sensor T2 is equal to or higher than the defrost release temperature X ° C., the defrost operation release unit 10a cancels the defrost operation. Therefore, even if the defrost release determination using the discharge pipe temperature characteristic during the defrost operation is delayed, the defrost operation can be reliably released.

  In the second embodiment, during the defrost operation, the evaporator temperature determination unit 10b determines that the evaporator temperature detected by the evaporator temperature sensor T2 is lower than the defrost release temperature, and the discharge pipe temperature sensor. When the discharge pipe temperature determination unit 10c determines that the discharge pipe temperature detected by T1 has increased by a predetermined temperature from the lowest temperature during the defrost operation, the defrost operation is released by the defrost operation release unit 10a, but the evaporator temperature is determined. The defrosting operation may be canceled by changing the discharge pipe temperature (increase from the minimum temperature).

[Third Embodiment]
FIG. 9 is a flowchart for explaining the operation during the defrosting operation of the control device 10 of the heat pump apparatus according to the third embodiment of the present invention. The heat pump device according to the third embodiment has the same configuration as that of the heat pump device according to the first embodiment except for the control device 10, and uses FIG.

  First, when the process starts, as shown in FIG. 9, the defrost operation is started in step S21. That is, during the boiling operation, the boiling circulation pump that circulates the water in the hot water storage tank through the condenser 2 is stopped, the opening of the electric expansion valve EV is fully opened, and the operating frequency of the compressor 1 To the frequency during defrost operation.

  Next, the process proceeds to step S22, and the evaporator temperature is detected by the evaporator temperature sensor T2.

  Next, it progresses to step S23 and it is determined by the 1st evaporator temperature determination part 10b whether an evaporator temperature is more than defrost cancellation | release temperature X degreeC. When the first evaporator temperature determination unit 10b determines in step S23 that the evaporator temperature is equal to or higher than the defrost release temperature X ° C., the process proceeds to step S27, where the defrost operation release unit 10a cancels the defrost operation. The process ends.

  On the other hand, if the first evaporator temperature determination unit 10b determines in step S23 that the evaporator temperature is lower than the defrost release temperature X ° C., the process proceeds to step S24.

  In step S24, the discharge pipe temperature is detected by the discharge pipe temperature sensor T1.

  Next, it progresses to step S25 and it is determined by the discharge pipe temperature determination part 10c whether the discharge pipe temperature changed from the fall to the raise. That is, it is determined whether or not the discharge pipe temperature has changed from falling to rising after the start of the defrost operation.

  If the discharge pipe temperature determination unit 10c determines in step S25 that the discharge pipe temperature has changed from a decrease to an increase, the process proceeds to step S27, where the defrost operation is canceled by the defrost operation cancellation unit 10a, and this process ends. Here, before proceeding from step S25 to step S27, after waiting for a predetermined time (in this embodiment, 30 seconds), the process may proceed to step S27 so as to allow the release of the defrost operation to be given a margin.

  On the other hand, if the discharge pipe temperature determination unit 10c determines in step S25 that the discharge pipe temperature has not changed from a decrease to an increase, the process proceeds to step S26, where the discharge pipe temperature determination unit 10c changes the discharge pipe temperature from the lowest temperature to a predetermined temperature A. Judge whether the temperature has risen. That is, it is determined whether or not the discharge pipe temperature has increased by a predetermined temperature A ° C. from the lowest temperature after the start of the defrost operation.

  When the discharge pipe temperature determination unit 10c determines in step S26 that the discharge pipe temperature has increased from the lowest temperature by a predetermined temperature A ° C, the process proceeds to step S27, where the defrost operation is released by the defrost operation release unit 10a, and this process is performed. finish.

  On the other hand, when the discharge pipe temperature determination unit 10c determines in step S26 that the discharge pipe temperature has not risen from the lowest temperature by the predetermined temperature A ° C., the process returns to step S22, and steps S22 to S26 are repeated.

  As described above, in the heat pump device of the third embodiment, the first evaporator temperature determination unit 10b when the evaporator temperature detected by the evaporator temperature sensor T2 is lower than the defrost release temperature X ° C. during the defrost operation. Or the discharge pipe temperature determination unit 10c determines that the discharge pipe temperature detected by the discharge pipe temperature sensor T1 has changed from a decrease after the start of the defrost operation to an increase, or the discharge pipe temperature sensor When the discharge pipe temperature determination unit 10c determines that the discharge pipe temperature detected by T1 has increased by a predetermined temperature A ° C from the lowest temperature during the defrost operation, the defrost operation release part 10a cancels the defrost operation. Since the defrost operation is canceled by any one of these three condition determinations, the evaporator 4 can be reliably defrosted.

  In the first to third embodiments, the heat pump device used in the hot water storage type hot water heater has been described. However, the heat pump of the present invention is not limited to the hot water storage type hot water heater, and other devices such as a floor heating device and an air conditioner. An apparatus may be applied.

In the above-mentioned first to third embodiments, the heat pump apparatus was using CO ₂ refrigerant, may use other refrigerants such as NH ₃ refrigerant or R22 refrigerant.

  Although specific embodiments of the present invention have been described, the present invention is not limited to the first to third embodiments, and various modifications can be made within the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Compressor 2 ... Condenser 3 ... Gas heat exchanger 4 ... Evaporator 5 ... Accumulator 6 ... Blower fan 10 ... Control apparatus 10a ... Defrost operation cancellation | release part 10b ... Evaporator temperature determination part 10c ... Discharge pipe temperature determination part T1 ... discharge pipe temperature sensor T2 ... evaporator temperature sensor T3 ... outside air temperature sensor T4 ... incoming water temperature sensor T5 ... hot water temperature sensor

Claims (4)

A refrigerant circuit having a compressor (1), a condenser (2), an electric expansion valve (EV), and an evaporator (4);
A discharge pipe temperature sensor (T1) for detecting the discharge pipe temperature of the compressor (1);
A control device (10) for performing a positive cycle defrost operation by fully opening the electric expansion valve (EV),
The control device (10) includes a defrost operation canceling unit (10a) for canceling the normal cycle defrost operation based on the discharge tube temperature detected by the discharge tube temperature sensor (T1). . In the air conditioner according to claim 1,
An evaporator temperature sensor (T2) for detecting the temperature of the evaporator (4);
The control device (10) includes an evaporator temperature determination unit (10b) for determining whether or not the evaporator temperature detected by the evaporator temperature sensor (T2) is equal to or higher than a defrost release temperature,
The defrost operation canceling unit (10a) is configured such that during the positive cycle defrost operation, the evaporator temperature detected by the evaporator temperature sensor (T2) by the evaporator temperature determination unit (10b) is equal to or higher than the defrost release temperature. When it is determined that there is a heat pump device, the forward cycle defrost operation is canceled. In the air conditioner according to claim 1 or 2,
Whether the discharge device temperature detected by the discharge tube temperature sensor (T1) has changed from a decrease after the start of the positive cycle defrost operation to an increase during the normal cycle defrost operation. A discharge pipe temperature determination unit (10c) for determining whether or not,
The defrosting operation cancellation unit (10a) is configured such that the discharge pipe temperature determination unit (10c) detects the discharge pipe temperature detected by the discharge pipe temperature sensor (T1) during the positive cycle defrosting operation, as the positive cycle. The heat pump device according to claim 1, wherein the forward cycle defrost operation is canceled when it is determined that the change from the lowering to the rising after the start of the defrosting operation. In the air conditioner according to claim 1 or 2,
The control device (10) determines whether the discharge pipe temperature detected by the discharge pipe temperature sensor (T1) has increased by a predetermined temperature from the lowest temperature during the positive cycle defrost operation during the positive cycle defrost operation. A discharge pipe temperature determination unit (10c) for determining whether
The defrosting operation cancellation unit (10a) is configured such that the discharge pipe temperature determination unit (10c) detects the discharge pipe temperature detected by the discharge pipe temperature sensor (T1) during the positive cycle defrosting operation, as the positive cycle. A heat pump device that releases the positive cycle defrost operation when it is determined that the predetermined temperature has risen from the lowest temperature during the defrost operation.

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