JP4622921B2 - Air conditioner - Google Patents

Description

  The present invention relates to an air conditioner that performs a defrosting operation for defrosting frost adhering to an outdoor heat exchanger.

  Conventionally, this type of air conditioner switches the four-way valve when heating operation is stopped, and flows the refrigerant in the refrigeration cycle in the opposite direction to that during heating, that is, the same refrigerant flow direction as in cooling, and the outdoor heat exchanger has a high temperature and high pressure. After the defrosting operation is performed by the defrosting method in which the frost attached to the outdoor heat exchanger is melted by flowing the refrigerant, the operation of the air conditioner is stopped. Thereby, since it can stop after fully performing defrost especially at the time of heating operation stop especially at night, the capability shortage by frost at the time of the heating operation start of the next morning can be prevented (for example, refer patent document 1).

  On the other hand, in this type of defrosting system, the indoor heat exchanger becomes an evaporator during defrosting, so there is a basic problem that the temperature of the room in the room decreases and a cold air feeling is felt. As a countermeasure against the problem, as a defrosting method in which the defrosting operation is performed while continuing the heating, a refrigerant heating circuit having a refrigerant heater and a defrosting circuit are provided in the refrigeration cycle, and the refrigerant heated by the refrigerant heater is replaced with a compressor. After passing through, the flow branches through the flow through the indoor heat exchanger and the flow into the outdoor heat exchanger through the defrosting circuit in the opposite direction to that during heating, and the indoor heating by the indoor heat exchanger and the outdoor heat exchanger There exists what performs a defrost simultaneously (for example, refer patent document 2).

  FIG. 9 shows a configuration diagram of a refrigeration cycle of a conventional air conditioner described in Patent Document 2. As shown in FIG. As shown in FIG. 9, in a heat pump refrigeration cycle in which a compressor 101, a four-way valve 102, an indoor heat exchanger 110, an expansion mechanism 105, and an outdoor heat exchanger 103 are connected by a refrigerant circuit, the expansion mechanism 105 and the outdoor heat A refrigerant heating circuit having a refrigerant heater 104 connected between the exchangers 103 and the suction side of the compressor 101, a discharge side of the compressor 101, and between the outdoor heat exchanger 103 and the four-way valve 102 When the defrosting of the outdoor heat exchanger 103 is performed, the refrigerant heated by the refrigerant heater 104 passes through the compressor 101 and then flows through the indoor heat exchanger 110. And the flow through the outdoor heat exchanger 103 via the circuit for defrosting, and the flow of the branched refrigerant merges at the inlet of the refrigerant heating circuit and is heated by the refrigerant heater 104 again. Been That.

From the above conventional invention, after the heating operation, the outdoor heat exchanger can be sufficiently defrosted without causing a feeling of cold air accompanying a decrease in the room temperature, so that it can be stopped at the start of the heating operation the next morning. Insufficient capacity can be prevented. Further, by performing the defrosting operation without switching the four-way valve, there is no sense of discomfort or discomfort due to the switching sound.
Japanese Patent Laid-Open No. 61-17870 JP-A-11-182994

  However, in the conventional configuration, although the compressor is operated and defrosted while the heating operation is stopped, refrigerant noise is generated, which may give the user a sense of discomfort and discomfort. Had problems.

  The present invention solves the above-mentioned conventional problems, and does not give the user a sense of incongruity or discomfort, and allows the outdoor heat exchanger to be defrosted without causing a feeling of cold air accompanying a decrease in indoor temperature. It aims at providing the air conditioner which performs enough.

In order to solve the above-described conventional problems, the air conditioner of the present invention is configured so that the refrigerant flows in the order of the compressor, the four-way valve, the indoor heat exchanger, the decompressor, the outdoor heat exchanger , and the four-way valve during heating operation. a heat pump type refrigeration cycle linked to, and a indoor blower for blowing into the indoor heat exchanger, said in the heat pump type refrigeration cycle, and between said pressure reducer and said indoor heat exchanger, and the four-way valve A first bypass circuit connecting between the outdoor heat exchanger and the first bypass circuit connecting between the indoor heat exchanger and the compressor, and between the pressure reducer and the outdoor heat exchanger. 2
The first bypass circuit is provided with a refrigerant heating two-way valve and a refrigerant heater having a refrigerant passage therein, and the second bypass circuit is provided with a defrosting two-way valve When performing the defrosting of the outdoor heat exchanger, the refrigerant heating two-way valve and the two-way defrosting valve are opened, and the refrigerant flowing through the first bypass circuit is passed through the refrigerant heater. An air conditioner for performing a first bypass operation for heating and a second bypass operation for allowing the refrigerant compressed by the compressor to pass through the outdoor heat exchanger, and at the end of the heating operation, first, the refrigerant The two-way valve for heating is opened, the pressure reducer is substantially closed, a first bypass operation is performed in which a refrigerant flows through the first bypass circuit, and the two-way valve for defrosting is controlled to open in a predetermined time. The second bypass operation in which the refrigerant flows through the second bypass circuit. There further the indoor blower continues to operate at very small rotational performs defrosting operation of the outdoor heat exchanger, the defrosting operation is one that stops the operation of the compressor after completion.

As a result, at the end of the heating operation, the refrigerant heated by the refrigerant heater is allowed to flow to the outdoor heat exchanger, so that defrosting can be performed without switching the four-way valve, and the rise in the temperature of the indoor heat exchanger is mitigated, and the squeak is caused by thermal expansion. This has the effect of preventing the generation of noise and lowering the suction pressure of the compressor, thereby avoiding high frequency and high suction pressure operation and improving the reliability of the compressor. to not feel the feeling, Ru can be carried out defrosting of the outdoor heat exchanger enough.

  The air conditioner of the present invention can perform a stable defrosting operation without giving the user a sense of discomfort or discomfort, and without feeling the cold air accompanying a decrease in the room temperature, and is sufficient from the start of the next operation. Therefore, a comfortable air-conditioning environment can be stably provided at a lower cost to the user.

The air conditioner of the first invention includes a heat pump refrigeration cycle in which a refrigerant flows in the order of a compressor, a four-way valve, an indoor heat exchanger, a decompressor, an outdoor heat exchanger , and the four-way valve during heating operation. And an indoor fan for blowing air to the indoor heat exchanger, and in the heat pump refrigeration cycle, between the indoor heat exchanger and the pressure reducer, and between the four-way valve and the outdoor heat exchanger. And a second bypass circuit that connects between the indoor heat exchanger and the compressor, and between the decompressor and the outdoor heat exchanger, The first bypass circuit is provided with a refrigerant heating two-way valve and a refrigerant heater having a refrigerant flow passage therein, the second bypass circuit is provided with a defrosting two-way valve, and the outdoor heat exchanger When performing defrosting, the refrigerant heating two-way valve and A first bypass operation for opening the two-way valve for defrosting and heating the refrigerant flowing in the first bypass circuit by the refrigerant heater, and the refrigerant compressed by the compressor in the outdoor heat exchanger The air conditioning apparatus performs the second bypass operation that passes through the air, and at the end of the heating operation, first, the refrigerant heating two-way valve is opened to substantially close the pressure reducer, and the refrigerant is supplied to the first bypass circuit. A first bypass operation is performed, and after a predetermined time has elapsed, a second bypass operation is performed in which the two-way valve for defrosting is controlled to open to flow a refrigerant through a second bypass circuit, and the indoor fan The operation continues with a slight rotation, performs the defrosting operation of the outdoor heat exchanger, and stops the operation of the compressor after the defrosting operation is completed, thereby causing uncomfortable feeling due to the refrigerant sound and the switching sound of the four-way valve.・ Do not give the user discomfort Further, without feel cold wind feeling due to lowering of the room temperature, it can be determined promptly by using an defrosting of the outdoor heat exchanger sufficiently.

  In addition, since the defrosting circuit is performed outdoors even when the length of the connecting pipe becomes long, the compressor oil level in the defrosting operation by the pipe length does not decrease, and the compressor can be operated with high reliability even with long pipe products.

In addition, since a part of the whole refrigerant is used for defrosting, an extremely large amount of refrigerant does not flow through the refrigerant heating unit, so that a compact refrigerant heater can be used.

Even when the cooling operation is performed, high-temperature and high-pressure refrigerant gas stays in the refrigerant heater, and the refrigerant heater is always kept above the dew point temperature of the atmosphere, so that no condensation occurs in the refrigerant heater. .

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

(Embodiment 1)
FIG. 1 shows a representative configuration diagram of an air conditioner according to a first embodiment of the present invention.

  In FIG. 1, the outdoor unit 20 includes a compressor 1, a four-way valve 2, a decompressor 4, an outdoor heat exchanger 5, and an outdoor blower 19. The decompressor 4 here may be an electromagnetic expansion valve.

  The indoor unit 18 includes the indoor heat exchanger 3 and the indoor blower 17.

  Further, the outdoor unit 20 is provided with a first bypass circuit 6 and a second bypass circuit 9. The first bypass circuit 6 connects between the indoor heat exchanger 3 and the decompressor 4, and between the four-way valve 2 and the outdoor heat exchanger 5, and includes a refrigerant heating two-way valve 7 and a refrigerant heating decompressor. 12, a refrigerant heater 8 including a refrigerant heater 13, a refrigerant passage pipe part 14, and a heat storage part 15 is provided.

  The second bypass circuit 9 connects between the four-way valve 2 and the indoor heat exchanger 3, and between the pressure reducer 4 and the outdoor heat exchanger 5, and includes a defrosting two-way valve 10 and a defrosting pressure reduction. A container 11 is provided. The second bypass circuit 9 may connect between the compressor 1 and the four-way valve 2 and between the decompressor 4 and the outdoor heat exchanger 5.

  In the normal heating operation, the refrigerant heating two-way valve 7 and the defrosting two-way valve 10 are closed, the refrigerant does not flow through the first bypass circuit 6 and the second bypass circuit 9, and the compressor 1 compresses the refrigerant. The resulting refrigerant passes through the four-way valve 2, is condensed in the indoor heat exchanger 3, and dissipates heat to the indoor air. Further, the pressure is reduced by the pressure reducer 4 and evaporated by the outdoor heat exchanger 5 to take in the amount of heat from the outdoor air, return to the compressor 1 again, and be compressed again to heat the room.

  However, when the outdoor air temperature is very low, such as below zero, frost adheres to the outdoor heat exchanger 5, the heat exchange efficiency with the outdoor air is reduced, and the heating capacity is reduced, so that it is necessary to defrost.

  In particular, when the nighttime heating operation is stopped in winter, when the defrosting is not sufficiently performed, when the heating operation in the next morning is started, the defrosting operation is not performed immediately after the heating operation is started because the previous night's defrosting is not sufficient. In order to start, the heating capacity is insufficient and the start-up speed is further slowed down, so that the user's request cannot be met especially at the start of heating in the early winter season when heating capacity and start-up speed are required. Defrosting of the outdoor heat exchanger is necessary.

  FIG. 2 is a control block diagram according to the first embodiment of the present invention, and FIG. 3 is a time chart of control according to the first embodiment of the present invention.

  In FIG. 2, the defrosting start determination is made by the defrosting start determining means 50 on the outdoor unit side, and when it is determined that the defrosting is started, the compressor operating means 51, the refrigerant heating two-way valve opening / closing means 52, and the defrosting two-way The defrosting operation is performed by the valve opening / closing means 53, the expansion valve opening varying means 54, the outdoor fan operating means 55, the four-way valve switching means 56, and the heater heater operation stopping means 57 performing the respective operations.

  At this time, the defrost start signal from the outdoor unit 20 is received by the defrost start signal receiving means 58 of the indoor unit 18, and the indoor fan 17 is controlled by the indoor fan operating means 59 based on the determination of the defrost operation.

  As shown in FIG. 3, when it is determined that the defrosting is started at the end of the heating operation, the heating operation by the heat pump in Step 1 is shifted to the defrosting operation by the refrigerant heating operation in Step 2. In the present embodiment, defrosting is performed every time the heating operation is completed, but the determination condition for starting defrosting may be set according to the temperature of the outdoor heat exchanger or the like.

  In Step 2, first, the refrigerant heating two-way valve 7 is turned on and controlled in the opening direction, and the refrigerant heater 13 is turned on to connect the first bypass circuit 6 to perform the refrigerant heating operation. At this time, the expansion valve, which is the pressure reducer 4, performs an operation close to or close to closing.

  Therefore, most of the refrigerant condensed in the indoor heat exchanger 3 flows into the first bypass circuit 6, and passes through the refrigerant in the refrigerant heater 8 through the refrigerant heating two-way valve 7 and the refrigerant heating decompressor 12. It passes through the pipe part 14 and is heated by the refrigerant heater 13.

  Further, the slight refrigerant that has flowed to the outdoor heat exchanger 5 without passing through the first bypass circuit 6 joins again with the refrigerant heated in the first bypass circuit 6 before the four-way valve 2. Since the four-way valve 2 remains in the heating circuit and is not switched during defrosting, the refrigerant passes through the four-way valve 2 and is compressed by the compressor 1.

  The operating frequency of the compressor 1 is changed from Hzb1 in step 1 to Hzb2 in step 2. Hzb1 and Hzb2 may have the same frequency.

  Moreover, the indoor blower 17 stops. As a result, the amount of heat exchange in the indoor heat exchanger 3 is reduced, and a larger amount of heat can be used for defrosting the outdoor heat exchanger 5, and since heating operation is stopped, it is unnecessary for the user. The defrosting operation can be performed without feeling uncomfortable.

  Note that the indoor blower 17 may be continuously operated with a slight rotation so as not to give a sense of incongruity to the fact that it is stopped. As a result, the rise in the temperature of the indoor heat exchanger 3 can be mitigated and the occurrence of squeak noise due to thermal expansion can be prevented, and the suction pressure of the compressor 1 can be reduced, thereby avoiding high frequency and high suction pressure operation. Reliability can be improved.

  Next, in step 3, in order to defrost the outdoor heat exchanger 5, the two-way valve 10 for defrosting is turned on and controlled in the opening direction, and the second bypass circuit 9 is made conductive. The compressor 1 is operated at an operating frequency Hzb3 for defrosting. The outdoor blower 19 is turned off (stopped).

  As a result, a part of the refrigerant compressed by the compressor 1 into a state sufficient for defrosting of the outdoor heat exchanger 5 flows into the second bypass circuit 9, and the defrosting two-way valve 10 and the defrosting decompression. It passes through the vessel 11 and enters the outdoor heat exchanger 5. Since the refrigerant is compressed to a state sufficient for defrosting of the outdoor heat exchanger 5 and the outdoor blower 19 is stopped, the refrigerant hardly exchanges heat with the outdoor air. The amount of heat is used for defrosting.

  Through the above steps, a stable defrosting operation is performed without feeling the feeling of cold air accompanying a decrease in the room temperature. After the defrosting of the outdoor heat exchanger 5 is completed, in step 4, during the defrosting of the outdoor heat exchanger The stored heat is dissipated and the ice frost around the outdoor blower 19 is melted.

Step 4 is an operation for opening the refrigerant heating two-way valve 7ON, a refrigerant heating operation for the refrigerant heater 13ON, and the expansion valve as the decompressor 4 being closed or close to closing, that is, conducting the first bypass circuit 6. The defrosting two-way valve 10 is shut off and the second bypass circuit 9 is shut off, the compressor 1 is changed to the operating frequency Hzb4, and the outdoor fan 19 is operated. And The operation frequency Hzb4 of the compressor 1 may be the same as the operation frequency Hzb2 before defrosting, and in that case, the control is exactly the same as in Step 2.

  Therefore, most of the refrigerant condensed in the indoor heat exchanger 3 flows into the first bypass circuit 6, and passes through the refrigerant in the refrigerant heater 8 through the refrigerant heating two-way valve 7 and the refrigerant heating decompressor 12. It passes through the pipe part 14 and is heated by the refrigerant heater 13.

  The slight amount of refrigerant that has flowed to the outdoor heat exchanger 5 without passing through the first bypass circuit 6 still has a sufficient amount of heat, and the amount of heat stored in the outdoor heat exchanger 5 during defrosting. Therefore, the amount of heat is transferred to the outdoor blower 19 and the ice frost around the outdoor blower 19 is melted.

  Thereafter, the refrigerant that has passed through the outdoor heat exchanger 5 joins again with the refrigerant heated in the first bypass circuit 6 before the four-way valve 2, passes through the four-way valve 2, and is compressed by the compressor 1.

  In the present embodiment, the indoor blower 17 remains stopped, but it may be operated with a slight rotation that does not give a sense of incongruity to the stopped state. As a result, the rise in the temperature of the indoor heat exchanger 3 is moderated to prevent the occurrence of squeaking noise due to thermal expansion, and the compressor 1 is improved in reliability by avoiding high frequency and high suction pressure operation due to the effect of lowering the suction pressure of the compressor 1. be able to.

  Through the above steps 2 to 4, the defrosting of the outdoor heat exchanger 5 and the melting of the ice frost around the outdoor blower 19 are completed. Next, in step 5, the normal heat pump heating operation is once returned to the operation of the compressor 1. The frequency is changed to Hzb5, and the compressor 1 is ready to be stopped. In step 6, the operation of the compressor 1, the outdoor fan 19, and the indoor fan 17 is stopped (the compressor operating frequency Hzb6 is set to 0). Note that step 5 for returning to the normal heat pump heating operation may be omitted.

  FIG. 4 is a comparison diagram of compressor operating frequencies at each step during normal defrosting and during defrosting during stop according to the first embodiment of the present invention.

  As shown in FIG. 4, by distinguishing the compressor operating frequency Hza at the time of normal defrosting from the compressor operating frequency Hzb at the time of defrosting, the refrigerant sound during the defrosting at the time of stopping can be reduced.

  The same effect can be obtained by changing conditions other than the compressor operating frequency, such as the defrosting time and the defrosting end condition, during normal defrosting and during defrosting during stoppage.

  Moreover, when utilizing the structure of the refrigeration cycle of the conventional air conditioner described in Patent Document 2, control is omitted because it is described in Patent Document 2, but the compressor frequency in each step is usually What is necessary is just to make it different at the time of defrosting at the time of defrosting at the time of a stop.

As described above, in the present embodiment, the heat pump refrigeration cycle is provided with a bypass circuit having a refrigerant heater, and when the heating operation ends, the refrigerant heated by the refrigerant heater is caused to flow to the outdoor heat exchanger. After the defrosting of the outdoor heat exchanger without switching the four-way valve, the air conditioner is stopped, and the operation continues at a slight rotation so as not to give a sense of incongruity that the indoor blower is stopped. As a result, the rise in the temperature of the indoor heat exchanger 3 can be mitigated and the occurrence of squeak noise due to thermal expansion can be prevented, and the suction pressure of the compressor can be reduced, thereby avoiding high frequency high suction pressure operation and the compressor. Reliability can be improved. In addition, the outdoor heat exchanger can be sufficiently defrosted without causing a feeling of cold air accompanying a decrease in indoor temperature.

  In particular, the bypass circuit includes a two-way valve and a refrigerant heater in a first bypass circuit that connects between the indoor heat exchanger and the decompressor connected to the refrigeration cycle, and between the four-way valve and the outdoor heat exchanger. Furthermore, between the four-way valve connected to the refrigeration cycle and the indoor heat exchanger, between the pressure reducer and the outdoor heat exchanger, or between the compressor connected to the refrigeration cycle and the four-way valve, and between the pressure reducer and the outdoor When the outdoor heat exchanger is defrosted by opening the two-way valve of the first bypass circuit, the refrigerant heater is configured by providing a two-way valve in the second bypass circuit connecting between the heat exchangers. Performing a first bypass operation in which the refrigerant heated in the flow to the suction side of the compressor and a second bypass operation in which the two-way valve of the second bypass circuit is opened to allow the refrigerant to pass through the outdoor heat exchanger. As a result, the refrigerant discharged from the compressor flows to the compressor suction side or is removed from the heating operation. Since the refrigerant flow in the outdoor heat exchanger is not reversed when switching to operation, it does not require an expensive two-way valve, can be configured with a simple bypass circuit, and a large amount of refrigerant circulates into the refrigerant heater. Therefore, there is no need to increase the size, there is no problem of refrigerant sound and pressure balance, and a stable defrosting operation that does not feel cold air due to a decrease in room temperature can be performed.

  In addition, since the defrosting circuit is performed outdoors even when the length of the connecting pipe becomes long, the compressor oil level in the defrosting operation by the pipe length does not decrease, and the compressor can be operated with high reliability even with long pipe products.

  In addition, since a part of the whole refrigerant is used for defrosting, an extremely large amount of refrigerant does not flow in the refrigerant heating unit, so that a compact refrigerant heater can be used.

  Even when the cooling operation is performed, high-temperature and high-pressure refrigerant gas stays in the refrigerant heater, and the refrigerant heater is always kept above the dew point temperature of the atmosphere, so that no condensation occurs in the refrigerant heater. .

( Reference example )
5, FIG. 6, FIG. 7, and FIG. 8 are representative configuration diagrams of an air conditioner according to a reference example of the present invention.

  5 and FIG. 6, FIG. 7, and FIG. 8 have the same configuration as FIG. 1 and are as described above, but the refrigerant flows in the direction of the arrow in the circuit represented by the solid line.

  In FIG. 5, when defrosting at the end of the heating operation, the refrigerant heated by the refrigerant heater 104 is compressed by the compressor 101 by closing the two-way valves 21 and 22 and shutting off the refrigerant circuit to the indoor heat exchanger 110. After passing through the outdoor heat exchanger 103 through the circuit for defrosting, and after defrosting, the refrigerant heater 104 heats again, so that the high-pressure discharged refrigerant from the compressor 101 and the refrigerant are heated. The energy from both of the units 104 can be used for the outdoor unit defrosting, and the defrosting operation can be shortened.

  Similarly, in FIG. 6, when defrosting at the end of the heating operation, all the refrigerant compressed by the compressor 1 is closed by closing the two-way valves 21 and 22 and shutting off the refrigerant circuit to the indoor heat exchanger 3. It flows into the second bypass circuit 9, passes through the defrosting two-way valve 10 and the defrosting decompressor 11, and is branched into a flow passing through the first bypass circuit 6 and a flow passing through the outdoor heat exchanger 5. After defrosting with the heat exchanger 5, it joins again with the refrigerant heated by the first bypass circuit 6 before the four-way valve 2, passes through the four-way valve 2, and is compressed by the compressor 1. That is, all of the energy from both the high-pressure discharged refrigerant from the compressor 1 and the refrigerant heater 8 can be used for the outdoor unit defrosting, and the defrosting operation can be shortened.

  Further, when the refrigerant is compressed in a state sufficient for the defrosting of the outdoor heat exchanger 5 by the compressor 1, the refrigerant heater 13 of the refrigerant heater 8 may be turned off to perform an energy saving operation.

  Further, in FIG. 7, when defrosting at the end of the heating operation, the two-way valves 21 and 22, the defrosting two-way valve 10 of the second bypass circuit 9 are closed, and the refrigerant circuit to the indoor heat exchanger 3, By shutting off the bypass circuit 9, the compressor 1 is stopped, all the refrigerant heated in the first bypass circuit 6 flows into the outdoor heat exchanger 5, and defrosting is performed in the outdoor heat exchanger 5. Thereafter, it is heated again by the first bypass circuit 6. Therefore, since the refrigerant does not flow to the second bypass circuit 9, the amount of heat is not wasted, and the outdoor unit can be defrosted more efficiently.

  In FIG. 8, when defrosting is performed at the end of the heating operation, the two-way valves 21 and 22, the refrigerant heating two-way valve 7 of the first bypass circuit 6 are closed, and the refrigerant circuit to the indoor heat exchanger 3, By shutting off the bypass circuit 1, the refrigerant heater 13 of the refrigerant heater 8 is turned OFF, and all the refrigerant compressed to a state sufficient for defrosting of the outdoor heat exchanger 5 by the compressor 1 is second. After passing through the defrosting two-way valve 10 and the defrosting decompressor 11 of the bypass circuit 9 to the outdoor heat exchanger 5 and defrosting with the outdoor heat exchanger 5, the compressor 1 again Compressed. Therefore, the outdoor unit can be defrosted with only the high-pressure discharged refrigerant from the compressor 1 and there is no waste of heat in the first bypass circuit 6, so that the energy saving operation is performed.

  As described above, in the present embodiment, when defrosting is performed at the end of the heating operation, the refrigerant circuit to the indoor heat exchanger of the refrigeration cycle is shut off, whereby both the high-pressure discharged refrigerant from the compressor and the refrigerant heater are used. All the energy can be used for the outdoor unit defrosting, and the defrosting operation can be shortened.

  Moreover, since the refrigerant does not flow to the second bypass circuit by closing the two-way valve of the second bypass circuit, the amount of heat is not wasted and the outdoor unit can be defrosted more efficiently.

  Further, by closing the two-way valve of the first bypass circuit, the refrigerant does not flow to the first bypass circuit, so that the amount of heat is not wasted, and the refrigerant heater is not used, Since the defrosting is performed only by the heat energy generated by the high-pressure discharge refrigerant, the outdoor unit can be defrosted with more energy saving.

  The refrigerant circuit to the indoor heat exchanger of the refrigeration cycle may be shut off and the second bypass circuit or the first bypass circuit may be shut off at the same time, or sequentially according to the state of the outdoor unit defrosting. You may go.

  For example, immediately after stopping the heating operation, only the refrigerant circuit is shut off to the indoor heat exchanger of the refrigeration cycle, and all the energy from both the high-pressure discharged refrigerant from the compressor 1 and the refrigerant heater 8 is used for the outdoor unit defrosting. When the frost is quickly removed and the frost is removed to some extent, the second bypass circuit or the first bypass circuit may be shut off to switch to the energy saving operation. Furthermore, you may combine with the defrost operation which does not interrupt | block the circuit shown in Embodiment 1. FIG.

  As described above, the air conditioner according to the present invention can perform a stable defrosting operation without causing the user to feel uncomfortable or uncomfortable, and without causing a feeling of cold air accompanying a decrease in room temperature. Since it becomes possible, it is applicable also to uses, such as a heat pump water heater.

Representative configuration diagram of an air conditioner according to Embodiment 1 of the present invention Control block diagram according to Embodiment 1 of the present invention Time chart of control in Embodiment 1 of the present invention Comparison chart of compressor operating frequency in each step during normal defrosting and defrosting during stop in Embodiment 1 of the present invention Representative configuration diagram of air conditioner in reference example Representative configuration diagram of air conditioner in reference example Representative configuration diagram of air conditioner in reference example Representative configuration diagram of air conditioner in reference example Configuration diagram of conventional air conditioner refrigeration cycle

DESCRIPTION OF SYMBOLS 1 Compressor 2 Four-way valve 3 Indoor heat exchanger 4 Pressure reducer 5 Outdoor heat exchanger 6 First bypass circuit 7 Two-way valve for refrigerant heating 8 Heater 9 Second bypass circuit 10 Two-way valve for defrosting 11 Removal Frost decompressor 12 Refrigerant heating decompressor 13 Heater heater 14 Refrigerant passage tube part 15 Heat storage part 17 Indoor fan 18 Indoor unit 19 Outdoor fan 20 Outdoor unit 21, 22 Two-way valve

Claims (1)

During heating operation, a compressor, a four-way valve, an indoor heat exchanger, a decompressor, an outdoor heat exchanger , a heat pump refrigeration cycle connected so that refrigerant flows in the order of the four-way valve, and a room for blowing air to the indoor heat exchanger A first bypass circuit that connects between the indoor heat exchanger and the decompressor, and between the four-way valve and the outdoor heat exchanger in the heat pump refrigeration cycle, and A second bypass circuit that connects between the indoor heat exchanger and the compressor and between the pressure reducer and the outdoor heat exchanger, the first bypass circuit being for heating the refrigerant When a two-way valve and a refrigerant heater having a refrigerant flow path are provided therein, a two-way valve for defrosting is provided in the second bypass circuit, and the defrosting of the outdoor heat exchanger is performed, the refrigerant Open the two-way valve for heating and the two-way valve for defrosting. The first bypass operation for heating the refrigerant flowing through the first bypass circuit with the refrigerant heater and the second bypass operation for allowing the refrigerant compressed by the compressor to pass through the outdoor heat exchanger are performed. In the air conditioner, at the end of the heating operation, first, the refrigerant heating two-way valve is opened, the decompressor is substantially closed, and a first bypass operation is performed in which the refrigerant flows through the first bypass circuit, and is performed for a predetermined time. After the elapse of time, the defrosting two-way valve is controlled in the opening direction to perform a second bypass operation for flowing the refrigerant to the second bypass circuit, and the indoor blower is continuously operated with a slight rotation, An air conditioner that performs a defrosting operation of an outdoor heat exchanger and stops the operation of the compressor after the defrosting operation is completed .

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