JP4830399B2 - Air conditioner - Google Patents

Description

  The present invention can perform a defrosting operation for defrosting the frost attached to the outdoor heat exchanger while continuing the heating during the heating operation by the heat pump operation, thereby reducing the change in the blowing temperature during the defrosting operation. The present invention relates to an air conditioner that improves comfort.

Conventionally, this type of heat pump air conditioner defrosting method generally switches the four-way valve,
A defrosting method is adopted in which the refrigerant in the refrigeration cycle is flowed in the reverse direction.

  That is, in the defrosting operation, the refrigerant flows in the same direction as during cooling, and a high-temperature and high-pressure refrigerant flows through the outdoor heat exchanger to melt the frost adhering to the heat exchanger. It is controlled to become.

  In this defrosting method, when the defrosting is performed, the indoor heat exchanger becomes an evaporator and the indoor blower is stopped, so there is a basic problem that the temperature of the indoor room is lowered and a cold wind feeling is felt. .

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

  FIG. 4 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 heating, if conditions are determined. (For example, refer to Patent Document 1).
Japanese Patent Laid-Open No. 11-182994 (FIG. 4)

  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 at one end, 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.

  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 there is a structural problem that the heater becomes large.

  Furthermore, when the cooling circuit is operated, the inside of the piping of the refrigerant heater 104 is stabilized with the low-pressure refrigerant, and the temperature of the refrigerant heater 104 is decreased. Therefore, when the dew condensation occurs on the refrigerant heater 104 or the two-way valve 108 breaks down, the refrigerant Even when leakage occurs, condensation occurs in the refrigerant heater, and there is a big problem in the reliability and safety of the refrigerant heater.

  The present invention has been made in view of the above-described problems of the prior art. A stable defrosting operation in which a refrigeration cycle can be configured with a simple bypass circuit and no problems of refrigerant noise and pressure balance occur. An object of the present invention is to provide an air conditioner that can be carried out while the operation is continued and that improves the comfort by reducing the change in blowing temperature during the defrosting operation.

In order to achieve the above object, the 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 indoor heat exchange. A first bypass circuit that connects between the compressor and the decompressor, and between the four-way valve and the outdoor heat exchanger, and a refrigerant heating two-way valve and a refrigerant heater provided in the first bypass circuit, 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. , A defrosting two-way valve provided in the second bypass circuit, an indoor pipe temperature sensor provided in the indoor heat exchanger, and air flow to the indoor heat exchanger An indoor blower that performs defrosting of the outdoor heat exchanger, With opening the serial refrigerant heating two-way valve, after the rotation speed of the indoor fan indoor piping temperature sensor is lowered in accordance with the indoor piping temperature detected, characterized in that opening the two-way valve for the defrosting It is what.

  The air-conditioning apparatus of the present invention can perform defrosting while continuing the heating operation, and can improve comfort with a small change in blowing temperature during the defrosting operation.

A first 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 between the indoor heat exchanger and the decompressor, and the four-way A first bypass circuit connecting between the valve and the outdoor heat exchanger, a refrigerant heating two-way valve and a refrigerant heater provided in the first bypass circuit, the four-way valve, and the indoor heat exchanger A second bypass circuit connecting 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, A defrosting two-way valve provided in the second bypass circuit, an indoor pipe temperature sensor provided in the indoor heat exchanger, and an indoor fan for blowing air to the indoor heat exchanger, the outdoor heat when performing the defrosting of the exchanger, it opened Then together the refrigerant heating two-way valve After the rotational speed of the indoor fan indoor piping temperature sensor is lowered in accordance with the indoor piping temperature detected by forming the configuration in which said opening the two-way valve for the defrosting, The defrosting operation can be performed while performing the heating operation.

  Further, since the defrosting operation is performed while heating is continued, no refrigerant noise is generated when the four-way valve is switched.

  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.

  Even when the cooling operation is performed, high-temperature and high-pressure refrigerant gas does not stay in the refrigerant heater, and the refrigerant heater does not cause dew condensation.

When defrosting the outdoor heat exchanger, the two-way valve for heating the refrigerant is opened , and after the rotational speed of the indoor blower is reduced by controlling the indoor piping temperature , the two-way valve for defrosting is opened . In addition, before opening the two-way valve for defrosting, the temperature change at the time of defrosting can be reduced and the comfort can be improved.

In the second aspect of the invention, particularly when the defrosting of the outdoor heat exchanger of the first aspect of the invention is performed, the refrigerant heating two-way valve is opened , and the rotational speed of the indoor blower is decreased to the maximum rotational speed. By providing the limit value, it is possible to prevent the blown wind from directly hitting a person and prevent the defrosting operation from being perceived, and at the same time, improve comfort.

  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-conditioning apparatus according to Embodiment 1 of the present invention. In the figure, an outdoor unit 21 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 two-way valve 11, first bypass circuit two-way valve 12, refrigerant heater 13, refrigerant passage pipe section 14, heat storage section 15, The outdoor blower 20 is provided. The indoor unit 19 is provided with the indoor heat exchanger 3, the indoor blower 17, and the indoor piping temperature sensor 18. 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.

  FIG. 5 shows an indoor piping temperature control diagram.

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 21 by the defrosting start signal receiving means 58 in the indoor unit 19, and the indoor fan 17 is controlled by the indoor fan operating means 59 based on the determination of the defrosting operation. Based on the temperature data recognized by the temperature sensor 18, the indoor fan 17 is controlled by the indoor fan operating means 59.

  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 a four-way valve continues heating, it does not switch during defrosting with a heating circuit.

  Moreover, since an internal fan continues heating, it does not stop and it performs indoor piping temperature control, and it provides it with the MAX limit value for rotation speed, and operates.

  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.

  Next, in step 4, the operation before defrosting is returned to when the defrosting is completed.

  Next, after step 5, the normal heat pump heating operation is resumed.

  In the first embodiment, the operating frequency of the compressor is changed, but the defrosting operation can be performed by continuing heating even with a constant speed compressor.

(Embodiment 2)
Next, Embodiment 2 will be described with reference to FIG.

  As shown in FIG. 4, 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 a four-way valve continues heating, it does not switch during defrosting with a heating circuit.

  Moreover, since an internal fan continues heating, it does not stop and it performs indoor piping temperature control, and it provides it with the MAX limit value for rotation speed, and operates.

  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.

Next, in step 4, the two-way valve for defrosting is turned off to complete the defrosting. Thereafter, after a predetermined time has elapsed, the refrigerant heating two-way valve OFF and the heater heater are turned OFF to complete the defrosting.

  Next, after step 5, the normal heat pump heating operation is resumed.

  In addition, since the same effect can be obtained with a variable capacity compressor, the compressor is expressed as a compressor here.

  As described above, the air-conditioning apparatus of the present invention can perform the defrosting operation while performing the heating operation, and thus can be applied to an air-conditioning apparatus in a cold district where the outdoor 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 Time chart of Embodiment 2 according to the present invention Indoor piping temperature control diagram according to the present invention Configuration of conventional air conditioner

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 pipe part 15 Heat storage part 17 Indoor blower 18 Indoor unit 19 Indoor piping temperature sensor 20 Outdoor blower 21 Outdoor unit

Claims (2)

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 between the indoor heat exchanger and the decompressor, the four-way valve and the outdoor heat exchange A first bypass circuit connecting between the heaters; a refrigerant heating two-way valve and a refrigerant heater provided in the first bypass circuit; between the four-way valve and the indoor heat exchanger; A second bypass circuit connecting between the compressor and the outdoor heat exchanger, or between the compressor and the four-way valve, and between the pressure reducer and the outdoor heat exchanger, and the second bypass circuit. A defrosting two-way valve provided in the indoor heat exchanger, an indoor pipe temperature sensor provided in the indoor heat exchanger, and an indoor fan that blows air to the indoor heat exchanger, and defrosting the outdoor heat exchanger making, as well as opening the refrigerant heating two-way valve, the indoor feeding After the rotational speed of the machine room pipe temperature sensor was reduced according to the indoor piping temperature detected, the air conditioner characterized by opening the two-way valve for the defrosting. When defrosting the outdoor heat exchanger, the two-way valve for heating the refrigerant was opened, a limit value was set for the maximum value of the rotational speed of the indoor blower, and the rotational speed of the indoor blower was reduced . 2. The air conditioning apparatus according to claim 1 , wherein the two-way valve for defrosting is opened afterwards .

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