JP2008116156A - Air conditioner - Google Patents

Abstract

An air conditioner capable of maintaining heating performance even under extremely low temperature conditions and capable of processing without a sense of incongruity when operation is stopped.
A bypass circuit having a refrigerant heater is provided in a heat pump refrigeration cycle in which a compressor, a four-way valve, an indoor heat exchanger, a decompressor, and an outdoor heat exchanger are connected by a refrigerant circuit, and only the outdoor unit is provided at the end of heating operation. The operation is continued, the refrigerant heated by the refrigerant heater is allowed to flow to the outdoor heat exchanger, and the heating cycle is maintained even when the outdoor heat exchanger is defrosted without switching the four-way valve. However, by performing the defrosting operation, the frosting of the outdoor heat exchanger is melted without a sense of incongruity such as refrigerant sound, and the performance at the next startup is ensured.
[Selection] Figure 1

Description

The present invention relates to defrosting operation control during heating operation in a heat pump air conditioner.

Conventionally, the defrosting operation of this type of heat pump air conditioner generally determines whether to perform the defrosting operation during the operation of the air conditioner.
In this defrosting method, when the heating operation is stopped immediately before the start of the defrosting operation and the heating operation is performed again, since the defrosting operation is not performed, the frost from the previous operation remains in the heat exchanger as it is, There was a problem that the capacity was reduced at the time of start-up and sufficient heating operation could not be performed. In particular, as the heating operation by the heat pump type air conditioner in the cold region with the recent improvement of the heating capacity has permeated, such a problem has been increasing.
As a countermeasure to this problem, it has been considered that the defrosting operation is determined even when the heating operation is stopped.

After the operation stop signal of the air conditioner is sent, it is determined whether to perform the defrosting operation.If the defrosting operation start condition is satisfied, the four-way switching valve is switched, and the refrigerant is in the reverse direction to the refrigeration cycle during heating, that is, It flows in the same direction as the refrigeration cycle during cooling, and melts frost attached to the heat exchanger by supplying high-temperature and high-pressure refrigerant to the outdoor heat exchanger, so that sufficient heating operation can be performed from the start of operation ( For example, see Patent Document 1).
Japanese Patent Laid-Open No. 61-17870

  However, in the conventional configuration in the previous period, although the operation stop instruction is issued, the air conditioner performs the defrosting operation while continuing the operation. Therefore, there is a difference between the user instruction and the actual operation. Had the problem of giving a sense of incongruity and discomfort. In addition, since the defrosting operation is performed by switching the four-way valve, there is a problem of giving a sense of incongruity and discomfort due to the switching sound and the pressure fluctuation sound.

  The present invention solves the conventional problems of the previous period, and only the outdoor unit is operated at the end of the heating operation, and the defrosting operation is performed to eliminate the difference between the user's instruction and the actual operation, thereby making the user feel uncomfortable. It aims at providing the air conditioning apparatus which can perform sufficient heating operation from the next operation start, without giving.

In order to achieve the above object, an air conditioner of the present invention includes a heat pump refrigeration cycle in which a compressor, a four-way valve, an indoor heat exchanger, a decompressor, and an outdoor heat exchanger are connected by a refrigerant circuit, an indoor unit, and an outdoor unit. A heat pump refrigeration cycle in which a compressor is provided with a blower, and a compressor, a four-way valve, an indoor heat exchanger, an expansion mechanism, and an outdoor heat exchanger are connected by a refrigerant circuit, the expansion mechanism in the refrigeration cycle and the outdoor Between the heat exchangers and between the suction side of the compressor, a refrigerant heating circuit having a refrigerant heater, between the discharge side of the compressor in the refrigeration cycle, the outdoor heat exchanger and the four-way valve And a circuit for defrosting the refrigerant, and when performing defrosting of the outdoor heat exchanger during the heat pump operation of the refrigeration cycle, the refrigerant heated by the refrigerant heater Then, the flow through the indoor heat exchanger and the flow from the defrosting circuit to the flow through the outdoor heat exchanger are branched, and the flow of these branched refrigerants merges at the inlet of the refrigerant heating circuit, It is configured to be heated again by the refrigerant heater.

  Furthermore, the air conditioner of the present invention comprises a heat pump refrigeration cycle in which a compressor, a four-way valve, an indoor heat exchanger, a decompressor, and an outdoor heat exchanger are connected by a refrigerant circuit, and a blower for each of the indoor unit and the outdoor unit. 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 is provided. A direction valve and a refrigerant heater are provided, and further connected 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 connected to the refrigeration cycle. A second bypass circuit is provided between the compressor and the four-way valve and between the pressure reducer and the outdoor heat exchanger, a two-way valve is provided in the second bypass circuit, and when the operation is stopped, Defrost the outdoor heat exchanger The open two-way valve in the first bypass circuit, is characterized in carrying out the opening to the defrosting operation of the two-way valve of the second bypass circuit.

  The air conditioning apparatus of the present invention can prevent a decrease in capacity due to frost formation at the start of the next heating operation by continuing the operation of only the outdoor unit after the operation is stopped and performing the defrosting operation.

  According to a first aspect of the present invention, there is provided a heat pump refrigeration cycle in which a compressor, a four-way valve, an indoor heat exchanger, a pressure reducer, and an outdoor heat exchanger are connected by a refrigerant circuit, and an air blower in each of the indoor unit and the outdoor unit. In a heat pump refrigeration cycle in which a four-way valve, an indoor heat exchanger, an expansion mechanism, and an outdoor heat exchanger are connected by a refrigerant circuit, between the expansion mechanism and the outdoor heat exchanger in the refrigeration cycle, the compressor A refrigerant heating circuit having a refrigerant heater, and a defrosting circuit for connecting the discharge side of the compressor, the outdoor heat exchanger, and the four-way valve in the refrigeration cycle. When the defrost of the outdoor heat exchanger is performed during the heat pump operation of the refrigeration cycle, the refrigerant heated by the refrigerant heater passes through the compressor and then flows through the indoor heat exchanger The defrosting circuit is branched into a flow passing through the outdoor heat exchanger, and the branched refrigerant flows merge at the inlet of the refrigerant heating circuit and are heated again by the refrigerant heater. With this configuration, when the operation is stopped, the defrosting operation is performed without giving a sense of incongruity or discomfort due to the switching sound by the four-way switching valve and the pressure fluctuation sound. Capability reduction due to frost formation can be prevented.

  Further, since the four-way valve is not switched during defrosting, the pressure fluctuation is small and the oil fluctuation of the compressor is small, so that the compressor can be operated with high reliability.

  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.

According to a second aspect of the present invention, there is provided a heat pump refrigeration cycle in which a compressor, a four-way valve, an indoor heat exchanger, a decompressor, and an outdoor heat exchanger are connected by a refrigerant circuit, and an indoor unit and an outdoor unit each equipped with a blower. A first bypass circuit that connects between the indoor heat exchanger and the pressure reducer connected in a cycle, and between the four-way valve and the outdoor heat exchanger is provided, and the two-way valve and the first bypass circuit are provided in the first bypass circuit. The compressor provided with a refrigerant heater and further connected between the four-way valve connected to the refrigeration cycle and the indoor heat exchanger, between the decompressor and the outdoor heat exchanger, or connected to the refrigeration cycle And the four-way valve, and a second bypass circuit that connects the pressure reducer and the outdoor heat exchanger, a two-way valve is provided in the second bypass circuit, and the outdoor heat exchange is performed when the operation is stopped. When defrosting the vessel, the first The defrosting operation is performed by opening the two-way valve of the bypass circuit and opening the two-way valve of the second bypass circuit. With this configuration, the switching sound by the four-way switching valve is obtained. In addition, the oil fluctuation of the compressor is small and the reliability of the compressor can be improved without giving a sense of incongruity or discomfort due to the pressure fluctuation sound. The number of way valves can be reduced, and a simple and inexpensive refrigeration cycle can be provided.

  Moreover, since the refrigerant after being defrosted and the refrigerant after being radiated by the indoor heat exchanger do not merge, refrigerant noise hardly occurs, and a refrigerant merger for solving the refrigerant noise problem is not required.

  Moreover, since the refrigerant circulation amount increases and the pressure loss increases at the junction, it is necessary to increase the pipe diameter as a countermeasure, and the heater is large, but such consideration is not necessary. Therefore, the heater can be designed compactly.

  In addition, when operating in a cooling circuit, the refrigerant heater piping is stable with high-pressure refrigerant and the temperature of the refrigerant heater does not decrease.Therefore, condensation occurs on the refrigerant heater or a refrigerant leaks due to a failure of the two-way valve. Even in this case, the condensation and the safety of the refrigerant heater can be improved without causing condensation in the refrigerant heater.

  3rd invention is equipped with the outdoor heat exchanger temperature detection apparatus which detects the temperature of an outdoor heat exchanger, and the outdoor temperature detection apparatus which detects outdoor temperature, and at the time of completion | finish of the heating operation of an air conditioning apparatus, at least said outdoor heat exchange By comparing the detection temperature from one of the detector temperature detector and the outside air temperature detector with a predetermined temperature set in advance, the amount of frost on the outdoor heat exchanger when heating operation is stopped is estimated, If it is determined that the amount of frost formation is small, the defrosting operation is not performed, so that the operation time can be shortened and a wasteful electricity bill can be saved.

  4th invention is equipped with the memory | storage device which memorize | stores the elapsed time after the completion | finish of the last defrost operation, and the predetermined time which preset the said elapsed time memorize | stored in the said memory | storage device at the time of the heating operation completion | finish of an air conditioning apparatus. By comparing with the time, the amount of frost formation on the outdoor heat exchanger when the heating operation is stopped is estimated, and if it is determined that the amount of frost formation is small, the defrosting operation is not performed, thereby shortening the operation time. It becomes possible to save useless electricity bills.

  5th invention is equipped with the memory | storage device which memorize | stores the cumulative operation time after completion | finish of the last defrost operation, and is predetermined by presetting the said cumulative operation time memorize | stored in the said memory | storage device at the time of the heating operation completion | finish of an air conditioning apparatus. The amount of frost formation on the outdoor heat exchanger when the heating operation is stopped is estimated by comparing with the time of heating, and if it is judged that the amount of frost formation is small, the defrosting operation is not performed, thereby further shortening the operation time. In addition, it is possible to save unnecessary electricity bills.

  In the sixth aspect of the present invention, when defrosting is performed at the end of the heating operation, it is possible to eliminate the difference between the user's operation and the actual operation by continuing the operation of only the outdoor unit and performing the defrosting operation.

  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 is a representative configuration diagram of an air conditioner according to the present invention. In the figure, an outdoor unit 20 includes a compressor 1, a four-way valve 2, a decompressor 4, an outdoor heat exchanger 5, a first bypass circuit 6, a refrigerant heating two-way valve 7, a refrigerant heater 8, a second Bypass circuit 9, defrosting two-way valve 10, second bypass circuit decompressor 11, first bypass circuit decompressor 12, refrigerant heater 13, refrigerant passage tube section 14, heat storage section 15, outdoor blower 19 is arranged. The indoor unit 18 is provided with the indoor heat exchanger 3 and the indoor blower 17. The decompressor 4 here may be an electromagnetic expansion valve.

  Next, FIG. 2 is a control block diagram showing the first embodiment according to the present invention, and FIG. 3 is a time chart showing the behavior when the control is operated. In FIG. 2, the defrosting start determination unit 50 determines whether to start defrosting when the operation is stopped on the outdoor unit side, and when it is determined that defrosting starts, the compressor operation unit 51, the refrigerant heating two-way valve opening / closing unit 52, and the defrosting unit. The two-way 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 perform the defrosting operation by performing the operations shown in FIG. .

  At this time, the defrosting start signal is received from the outdoor unit 20 by the defrosting start signal receiving means 58 in the indoor unit 18, and the operation of the indoor unit is stopped by the indoor unit operating means 59 from the determination of the defrosting operation.

  As shown in FIG. 3, when the start of defrosting is determined, the heating operation by the heat pump in step 1 is shifted to the heating operation by the refrigerant heating operation in step 2. At this time, the refrigerant heating two-way valve is turned on and controlled in the opening direction.

  Also, the heater is turned on to perform the refrigerant heating operation. At this time, the expansion valve performs a closed operation or an operation close to the closed state.

  In addition, the four-way valve is not switched during defrosting while maintaining the heating circuit.

  Next, in step 3, in order to perform defrosting, the two-way valve for defrosting is turned on and controlled in the opening direction. The compressor is operated at an operating frequency for defrosting. Also, the outdoor blower stops.

  Next, at step 4, the frost and ice melting operation around the outdoor fan is performed together with the completion of the defrosting.

  With the two-way valve for refrigerant heating opened, the two-way valve for defrosting is controlled to be closed and the outdoor fan is operated to dissipate the heat stored during defrosting to the outdoor heat exchanger, And melt ice.

  Next, at Step 5, the normal heat pump heating operation is temporarily returned, and after Step 6, the normal stop process is performed by stopping the compressor. At this time, step 5 of returning to the normal heat pump heating operation may be omitted.

  FIG. 4 is a graph showing another embodiment. When the outdoor heat exchanger temperature T and the set outdoor heat exchanger temperature Ta when the operation is stopped are compared, the outdoor air temperature t is compared with the set outdoor air temperature ta, and at least one of the detected temperatures is lower than the set temperature Estimating that the amount of frost on the outdoor heat exchanger when the heating operation is stopped is large, and if it is judged that the amount of frost is small, the defrosting operation is not performed, thereby shortening the operation time and reducing unnecessary electricity bills. It can be omitted. As a method for estimating the amount of frost formation when the heating operation is stopped, the relationship between the outdoor heat exchanger temperature and the outdoor air temperature may be determined as a simple primary expression as shown in FIG.

FIG. 6 is a flowchart showing still another embodiment. The defrosting operation is set to be performed only when the heating operation time Th and the heating operation accumulation time Tr are set to Th and Tr when the operation is stopped are larger than the set values Tha and Tra. In STEP 1 and 2, Th and Tr are reset, and in STEP 3, the heating operation is determined. If it is not heating operation, only Th is reset. In STEP 4, the operation time is counted, and in STEP 5, the defrosting operation is determined. If the defrosting operation is in progress, both Th and Tr are reset. When the heating operation stop operation is determined in STEP 6 and it is determined that the heating operation is stopped, in Step 7, Th, Tr and Tha, Tra are compared. Any one of Th or Tr is Tha,
When larger than Tra, after defrosting operation is performed in STEP8, the operation is stopped. By doing in this way, it becomes possible to shorten operation time and to save a wasteful electricity bill.

  FIG. 7 is a time chart showing still another embodiment. As shown in FIG. 7, the operation of the compressor and the outdoor fan is stopped during the operation stop operation. At this time, the expansion valve is in a fully open state or close to a fully open state. As described above, by performing the defrosting operation after stopping the operation once during the operation stop operation, it becomes possible to lower the indoor heat exchanger temperature at the start of the defrosting operation. The temperature rise of the heat exchanger temperature can be prevented, and the compressor reliability is improved.

  As described above, the air-conditioning apparatus of the present invention can perform the defrosting operation while performing the heating operation, and can perform the defrosting operation without a sense of incongruity when the operation is stopped, thereby greatly improving the rising performance as a result of the outdoor temperature. However, it can also be applied to an air conditioner in a cold region where the temperature is very low.

Configuration diagram of the air-conditioning apparatus according to Embodiment 1 of the present invention. Control block diagram according to the present invention Time chart of Embodiment 1 according to the present invention Parameter correlation diagram of another embodiment according to the present invention Parameter correlation diagram of another embodiment according to the present invention Flowchart of another embodiment according to the present invention Time chart of another embodiment according to the present invention Configuration of conventional air conditioner

Explanation of symbols

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 Defroster for frost 12 Depressurizer for refrigerant heating 13 Heater heater 14 Refrigerant passage pipe part 15 Heat storage part 17 Indoor blower 18 Indoor unit 19 Outdoor blower 20 Outdoor unit

Claims (6)

At least a compressor, a four-way valve, an indoor heat exchanger, a decompressor, and an outdoor heat exchanger are connected to the heat pump refrigeration cycle by a refrigerant circuit, and a bypass circuit having a refrigerant heater is provided. The air conditioner is characterized in that the outdoor heat exchanger is defrosted without switching the four-way valve by allowing the refrigerant superheated by the refrigerant heater to flow through the outdoor heat exchanger. The refrigeration cycle provided with the bypass circuit includes 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. A bypass circuit is provided with a two-way valve and a refrigerant heater, and is further connected between the four-way valve and the indoor heat exchanger connected to the refrigeration cycle, between the decompressor and the outdoor heat exchanger, or the refrigeration cycle. A second bypass circuit is provided between the compressor and the four-way valve connected to each other, and between the pressure reducer and the outdoor heat exchanger, and a two-way valve is provided in the second bypass circuit. A first bypass operation in which when the defrosting of the outdoor heat exchanger is performed, the two-way valve of the first bypass circuit is opened and the refrigerant heated by the refrigerant heater flows to the suction side of the compressor And open the two-way valve of the second bypass circuit Air conditioner according to claim 1, characterized in that the second bypass operation for passing the refrigerant to the serial outdoor heat exchanger. An outdoor heat exchanger temperature detection device for detecting the temperature of the outdoor heat exchanger; and an outdoor air temperature detection device for detecting the outdoor air temperature, and at the end of the heating operation of the air conditioner, at least the outdoor heat exchanger temperature detection device and the The detected temperature from either one of the outside air temperature detection devices is compared with a predetermined temperature set in advance, and if the temperature is lower than the predetermined temperature, the defrosting operation is performed. The air conditioning apparatus described in 1. A storage device that stores an elapsed time since the end of the previous defrosting operation is provided, and at the end of the heating operation of the air conditioner, the elapsed time stored in the storage device is compared with a predetermined time set in advance. The air conditioning apparatus according to any one of claims 1 to 3, wherein a defrosting operation is performed if the time is equal to or longer than a predetermined time. Comprising a storage device that stores the cumulative operation time since the end of the previous defrosting operation, at the end of the heating operation of the air conditioner, compare the cumulative operation time stored in the storage device with a predetermined time set in advance, The air-conditioning apparatus according to any one of claims 1 to 4, wherein a defrosting operation is performed if the time is equal to or longer than a predetermined time. 6. The air conditioner according to claim 1, wherein when the defrosting is performed at the end of the heating operation, only the outdoor unit is continuously operated at the end of the heating operation and the defrosting operation is performed.

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