JP2007051805A - Air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air conditioner performing a defrosting operation while continuing a heating operation. <P>SOLUTION: The air conditioner is provided with a first by-pass circuit 6 connecting the suction side of a compressor 1 to a part between an indoor heat exchanger 3 and a pressure reducer 4 of a heat pump type refrigerating cycle, the first by-pass circuit 6 comprising a two-way valve 7 and a refrigerant heater 8; and a second by-pass circuit 9 connecting a part between the pressure reducer 4 and an outdoor heat exchanger 5 to a part between the indoor heat exchanger 3 and a four-way valve 2 connected to the refrigerating cycle, the second by-pass circuit 9 comprising a two-way valve 10. When the outdoor heat exchanger 5 is defrosted, the two-way valve 7 of the first by-pass circuit 6 and the two-way valve 10 of the second by-pass circuit 9 are opened to perform the heating and defrosting operations. If sufficient defrosting cannot be performed in this defrosting method, four-way valve switching defrosting is performed in optimum conditions to suppress imperfect defrosting at the outdoor heat exchanger. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an air conditioner capable of performing a defrosting operation for defrosting frost adhering to an outdoor heat exchanger while heating is continued during a heating operation by a heat pump operation.

  Conventionally, this type of heat pump type air conditioner defrosting method generally employs a defrosting method in which the four-way valve is switched and the refrigerant of the refrigeration cycle is flowed in the reverse direction.

  That is, in the defrosting operation, the flow direction of the refrigerant is the same as that during cooling, and the frost attached to the heat exchanger is melted by flowing a high-temperature and high-pressure refrigerant through the outdoor heat exchanger.

  In this defrosting method, the indoor heat exchanger is an evaporator during defrosting, so the fan of the indoor unit is stopped. As a result, there is a basic problem that the temperature of the room is lowered to feel a cold wind.

  As a countermeasure to this basic problem, an invention for performing a defrosting operation while continuing a heating operation has been considered.

  FIG. 5 is a configuration diagram of a refrigeration cycle of a conventional air conditioner.

  As shown in the figure, in a heat pump refrigeration cycle in which 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 and the outdoor heat in the refrigeration cycle Between the exchangers and between the suction side of the compressor, a refrigerant heating circuit having a refrigerant heater, and between the discharge side of the compressor, the outdoor heat exchanger and the four-way valve in the refrigeration cycle. A defrosting circuit to be connected, and when defrosting the outdoor heat exchanger during the heat pump operation of the refrigeration cycle, after the refrigerant heated by the refrigerant heater passes through the compressor, 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 the branched refrigerant merges at the inlet of the refrigerant heating circuit, and again the refrigerant heater Thus the invention is configured is disclosed to be heated.

As taken up as a problem in the above invention, when performing a defrosting operation of the outdoor unit when performing a heat pump operation, it is possible to perform the defrosting operation while continuing the heating if conditions are determined. (For example, refer to Patent Document 1).
Japanese Patent Laid-Open No. 11-182994 (FIG. 6)

  However, this refrigeration cycle system has the following problems.

  In this refrigeration cycle, when the defrosting operation is performed, the two-way valve 109a is opened, and the refrigerant discharged from the compressor 101 flows between the outdoor heat exchanger 103 and the four-way valve 102. The two-way valve 106 is necessary so that the hot gas refrigerant to be defrosted does not flow to the compressor suction side.

The two-way valve 106 is connected to the suction side of the compressor 101, and in order to reduce the pressure loss during cooling and heating operation, the two-way valve 106 having a large diameter is adopted, which makes the two-way valve very expensive. End up.

  In addition, the two-way valve 108 is opened from the heat pump operation to switch to the refrigerant heating operation, and the refrigerant flow in the outdoor heat exchanger 103 is reversed in the method of performing the defrosting operation. Must be closed once, and a two-way valve 107 is required at the inlet of the outdoor heat exchanger 103.

  Therefore, this refrigeration cycle requires as many as four two-way valves, which is a complicated and expensive method.

  In addition, since the refrigerant after being defrosted and the refrigerant after being radiated by the indoor heat exchanger 110 merge, if the refrigerant pressure at the junction is higher than the refrigerant pressure after being defrosted, If the refrigerant flows through the heat exchanger and vice versa, the refrigerant will flow into the room, and the defrosting operation may not be performed while heating.

  In addition, since the refrigerant after being defrosted and the refrigerant radiated by the indoor heat exchanger 110 join together, refrigerant noise is likely to occur, and in order to solve the above pressure balance problem and refrigerant noise problem The case where a refrigerant merger is required can be considered.

  Further, 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. As a result, when superheated refrigerant discharged from a pipe with a large pipe diameter flows in, the refrigerant speed of the discharged gas decreases, and sufficient defrosting capacity cannot be ensured and frost may remain unmelted. There is.

  The present invention has been made in view of such problems of the prior art, and provides a stable defrosting operation in which the refrigeration cycle can be configured with a simple bypass circuit and the problem of refrigerant noise and pressure balance does not occur. At the same time, even if the frost of the outdoor heat exchanger is not melted during the defrosting operation of this hot gas bypass circuit, the four-way valve defrosting optimized according to the predetermined judgment conditions is sufficient to ensure comfort. It is an object of the present invention to provide a highly reliable air conditioner that performs defrosting completely.

  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, and the refrigeration cycle. A first bypass circuit that connects between the indoor heat exchanger and the pressure reducer connected to each other and between the four-way valve and the outdoor heat exchanger is provided, and a two-way valve and a refrigerant heater are provided in the first bypass circuit, Further, a second bypass that connects between the four-way valve and the indoor heat exchanger, between the pressure reducer and the outdoor heat exchanger, or between the compressor and the four-way valve, and between the pressure reducer and the outdoor heat exchanger. When the circuit is provided, the two-way valve is provided in the second bypass circuit, and the outdoor heat exchanger is defrosted, the two-way valve of the first bypass circuit is opened to compress the refrigerant heated by the refrigerant heater. The first bypass operation to flow to the suction side of the machine and the two-way valve of the second bypass circuit A second bypass operation is performed to allow the refrigerant to pass through the outdoor heat exchanger, and during the defrosting operation, the outdoor heat exchanger temperature detected by the temperature detector of the outdoor heat exchanger temperature within a predetermined time is predetermined. When the temperature does not reach, the defrosting method performed by the hot gas bypass is stopped and the refrigerant circuit is switched to a cooling cycle by the four-way valve to perform defrosting.

  The air conditioner of the present invention can perform defrosting while continuing the heating operation.

  A first invention includes a compressor, a four-way valve, an indoor heat exchanger, a decompressor, an outdoor heat exchanger having a detector for detecting an outdoor heat exchanger temperature, a heat pump refrigeration cycle connected by a refrigerant circuit, A first bypass circuit that connects the indoor heat exchanger and the pressure reducer connected to the refrigeration cycle, the four-way valve, and the outdoor heat exchanger is provided, and the two-way valve is provided in the first bypass circuit. And a refrigerant heater, and the compression 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 connected to the refrigeration cycle A second bypass circuit that connects 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 the outdoor heat exchanger When performing defrosting, the first bypass circuit A first bypass operation in which the two-way valve is opened and the refrigerant heated by the refrigerant heater flows to the suction side of the compressor, and the two-way valve of the second bypass circuit is opened, and the outdoor heat exchanger By performing a hot gas bypass defrosting configuration that performs a second bypass operation that allows the refrigerant to pass through, it is possible to perform the defrosting operation while performing the heating operation, and to remove the hot gas bypass. During the frost operation, when the outdoor heat exchanger temperature does not reach the predetermined judgment temperature of 6 ° C. or more within a predetermined time of 10 minutes and 30 seconds, the hot gas bypass defrost operation is immediately stopped and the four-way valve is switched to defrost. Change to the four-way valve switching defrost operation control.

  As a result, it is possible to prevent unmelted frost that may be generated due to a change in the outside air conditioning load, snow adhesion, freezing of the heat exchanger, variation in the heating amount of the refrigerant heater, and the like.

  The second invention adjusts the amount of heating of the refrigerant superheater performed during hot gas bypass defrosting according to the value of the outdoor air temperature detected by the outdoor air temperature detector of the first invention, and is optimal according to the load. By defrosting with a large amount of overheating, wasteful power consumption can be saved, and by optimizing the predetermined judgment time judged during hot gas bypass defrosting operation, four-way valve defrosting is wasted To reduce the comfort of heating operation.

  For example, by increasing the amount of heat of the refrigerant superheater when the outside air temperature is low and extending the determination time during the defrosting operation to 10 minutes 30 seconds or more, the defrosting operation is sufficiently performed and the comfort is also maintained. I can do it.

  The third aspect of the invention adjusts the amount of heating of the refrigerant superheater that is performed at the time of defrosting the hot gas bypass according to the value of the outdoor temperature detected by the outdoor temperature detector of the first aspect of the invention. By defrosting with a large amount of overheating, wasteful power consumption can be saved, and by optimizing the judgment temperature of the predetermined outdoor heat exchanger temperature judged during hot gas bypass defrosting operation, It is possible to suppress wasteful defrosting of the four-way valve and impairing the comfort of heating operation. For example, when the outside air temperature is low, the amount of heat of the refrigerant superheater is increased, and the determination temperature of the outdoor heat exchanger temperature during the defrosting operation is changed to 10 ° C. or more, thereby sufficiently performing the defrosting operation, Comfort can also be maintained.

  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 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, an outdoor heat exchanger temperature detector 21, an outdoor air temperature detector 22, and a first bypass circuit 6. , A refrigerant heating two-way valve 7, a refrigerant heater 8, a second bypass circuit 9, a defrosting two-way valve 10, a second bypass circuit two-way valve 11, a first bypass circuit two-way valve 12 The refrigerant heater 13, the refrigerant passage pipe part 14, the heat storage part 15, and the outdoor blower 19 are provided. 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 hot gas bypass defrost control is operated. FIG. 4 is a time chart when switching to four-way valve defrosting when the outdoor heat exchanger temperature does not reach the predetermined determination time and determination temperature during the hot gas bypass defrosting operation.

  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 performing the operations shown in FIG.

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

  The external fan stops during defrosting. Since the four-way valve continues heating, it remains in the heating circuit and does not switch during defrosting.

  Moreover, since an internal fan continues heating, it does not stop.

  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.

  Here, when the outdoor heat exchanger temperature does not reach the predetermined determination temperature within the predetermined determination time during the defrosting operation by the hot gas bypass control in step 3, the four-way valve shown in FIG. It moves to Step 1 in the time chart of defrost control, and preparations for four-way valve defrost control are started.

  Thereafter, the four-way valve defrosting is started in step 2, the compressor is started in step 3, and the four-way valve defrosting is continued.

  Here, during the defrosting operation, when the outdoor heat exchanger temperature reaches the determination temperature within a predetermined determination time, the four-way valve defrosting operation is terminated, and the process proceeds to step 4. Here, the heating operation is restored.

  Here, as an example, the connection of the first bypass circuit is made between the four-way valve and the outdoor heat exchanger, but the defrosting action is the same even between the four-way valve and the compressor suction side. The bypass circuit may be a four-way valve and a compressor suction side.

(Embodiment 2)
Next, a second embodiment will be described.

The present embodiment differs from the first embodiment in that the heating amount of the refrigerant superheater 8 is optimized and adjusted based on the temperature detected by the outdoor air temperature detector 22 in FIG. 1, and the defrost control in FIG. By optimizing the predetermined determination time in step 3 of the time chart, it is possible to suppress unnecessary shift to the four-way valve switching defrosting.

(Embodiment 3)
Next, a third embodiment will be described.

  The present embodiment differs from the first embodiment in that the heating amount of the refrigerant superheater 8 is optimized and adjusted based on the temperature detected by the outdoor air temperature detector 22 in FIG. 1, and the defrost control in FIG. By optimizing the predetermined determination temperature of the outdoor heat exchanger temperature in Step 3 of the time chart, it is possible to suppress the useless transition to the four-way valve switching defrosting.

  As described above, since the air conditioner of the present invention can perform the defrosting operation while performing the heating operation, it can be applied to an air conditioner in a cold region where the outdoor temperature is very low, and heat is also generated even if the defrost is performed. The problem that the frost attached to the exchanger remains undissolved can also be solved.

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 hot gas bypass defrosting according to Embodiment 1 of the present invention Time chart of four-way valve defrosting according to the first embodiment of the present invention Configuration diagram 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 fan 18 Indoor unit 19 Outdoor fan 20 Outdoor unit 21 Outdoor heat exchanger temperature detector 22 Outdoor air temperature detector

Claims (3)

Connected by a refrigerant circuit equipped with a compressor, a four-way valve, an indoor heat exchanger, a decompressor, an outdoor fan, a detector that detects the temperature of the outdoor heat exchanger and the outdoor heat exchanger, and a detector that detects the outdoor air temperature A heat bypass refrigeration cycle, 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 and a refrigerant heater are provided in one bypass circuit, and further between the four-way valve and the indoor heat exchanger connected to the refrigeration cycle, between the pressure reducer and the outdoor heat exchanger, or A second bypass circuit is provided to connect between the compressor and the four-way valve connected to a refrigeration cycle, and between the decompressor and the outdoor heat exchanger, and a two-way valve is provided in the second bypass circuit. Defrosting the outdoor heat exchanger When performing, the first bypass operation of opening the two-way valve of the first bypass circuit and flowing the refrigerant heated by the refrigerant heater to the suction side of the compressor, and two ways of the second bypass circuit The defrosting is performed by the hot gas bypass in the second bypass operation that opens the valve and allows the refrigerant to pass through the outdoor heat exchanger. During the defrosting operation, the temperature detector of the outdoor heat exchanger temperature is used within a predetermined time. When the detected outdoor heat exchanger temperature does not reach a predetermined temperature, the defrosting method performed by the hot gas bypass is stopped, and the refrigerant circuit is switched to a cooling cycle by the four-way valve to perform defrosting. Air conditioner. In the defrosting method performed by hot gas bypass, at the start of the defrosting operation, the heating amount of the refrigerant superheater is adjusted according to the value of the outdoor air temperature detected by the outdoor air temperature detector, and a predetermined time during the defrosting operation The air conditioner according to claim 1, wherein the air conditioner is changed. In the defrosting method performed by hot gas bypass, at the start of the defrosting operation, the heating amount of the refrigerant superheater is adjusted according to the value of the outdoor air temperature detected by the outdoor air temperature detector, and the predetermined amount during the defrosting operation is adjusted. The air conditioner according to claim 1, wherein the outdoor heat exchanger temperature is changed.

Images