JP4802602B2 - Air conditioner - Google Patents

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 air conditioner defrosting method generally employs a defrosting method in which the four-way valve is switched and the refrigerant in the refrigeration cycle flows in the reverse direction.

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

  In this defrosting method, since the indoor heat exchanger becomes an evaporator during defrosting, there is a basic problem that the temperature of the room in the room is lowered and a feeling of cold air is felt.

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

  FIG. 7 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 defrosting operation of the outdoor unit when performing heat pump operation, it is possible to perform defrosting operation while continuing heating if the conditions are limited. Yes (see, for example, Patent Document 1).
JP-A-11-182994

  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.

  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.

  Further, when operating in the cooling circuit, the refrigerant heater 104 inside the pipe is normally in a state where the temperature of the refrigerant heater 104 is lowered by the low-pressure refrigerant, so that condensation is likely to occur in the refrigerant heater 104. Even when refrigerant leaks due to failure of the way valve 108, condensation occurs in the refrigerant heater, and particularly when a heat transfer heater is used for the refrigerant heater, 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. It aims at providing the air conditioning apparatus which can be implemented while continuing a driving | operation.

In order to achieve the above object, an air conditioner according to 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. A first bypass circuit connecting between the inner heat exchanger and the pressure reducer, and between the four-way valve and the outdoor heat exchanger; between the four-way valve and the indoor heat exchanger; and the pressure reducer 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, A refrigerant heating two-way valve and a refrigerant heater in the bypass circuit, a defrosting two-way valve in the second bypass circuit, an outdoor temperature detecting means, the heat exchange between the indoor heat exchanger and the indoor air. An indoor fan that performs heat exchange between the outdoor heat exchanger and the outdoor air And when starting the defrosting operation, if the temperature detected by the outdoor temperature detection means is equal to or higher than a predetermined temperature, the decompressor is substantially closed, the refrigerant heater is turned on, and the refrigerant -out two-way valve for heating open, and the initial and predetermined period of the end of the defrosting operation to open the dividing two-way valve for frost, other than the predetermined period of the initial and final closes the two-way valve for the defrosting, The outdoor fan is stopped during a predetermined period in which the defrosting two-way valve is open, and the outdoor fan is operated in a period other than the predetermined period in which the defrosting two-way valve is open. When the temperature detected by the temperature detecting means is lower than a predetermined temperature, the pressure reducer is substantially closed, the refrigerant heater is turned on, and the refrigerant heating two-way valve and the defrosting two-way valve are turned on. It is characterized by opening.

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

A first aspect of the present invention relates to 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, between the indoor heat exchanger and the decompressor. A first bypass circuit that connects between the four-way valve and the outdoor heat exchanger, between the four-way valve and the indoor heat exchanger, and between the decompressor and the outdoor heat exchanger. Or a second bypass circuit connecting between the compressor and the four-way valve and between the pressure reducer and the outdoor heat exchanger, and a refrigerant heating two-way valve in the first bypass circuit; A refrigerant heater, a two-way valve for defrosting in the second bypass circuit, an outdoor temperature detection means, an indoor fan for exchanging heat between the indoor heat exchanger and indoor air, and outdoor heat exchange And an outdoor fan that exchanges heat between the outdoor air and the front fan when starting the defrosting operation. If the temperature detected by the outdoor temperature detecting means is equal to or higher than a predetermined temperature, and the pressure reducer substantially closed, and turn ON the refrigerant heater and-out the refrigerant heating two-way valve opens, and defrosting operation A predetermined period in which the two-way valve for defrosting is opened during a predetermined period of the initial period and the final period, and the two-way valve for defrosting is closed and the two-way valve for defrosting is opened except for the predetermined period of the initial period and the final period. Stops the operation of the outdoor fan, operates the outdoor fan except for a predetermined period in which the two-way valve for defrosting is open , and the temperature detected by the outdoor temperature detecting means is less than a predetermined temperature. In this case, the decompressor is substantially closed, the refrigerant heater is turned on, and the refrigerant heating two-way valve and the defrosting two-way valve are opened. The heating cycle of the room and the defrosting cycle outside the room Without supplying coolant to the side heat exchanger, it is possible to defrost the outdoor side of the air heat can be utilized to effect defrosting operation 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, some hot gas refrigerant can be supplied to the outdoor defrost cycle to make it easier to remove or dissolve frost attached to the outdoor heat exchanger, and to remove it in a short time by the heat of the outdoor air. Can be frosted. In addition, since the hot gas refrigerant can be supplied to the outdoor heat exchanger at the end of the defrosting period, the defrosting can be reliably completed.

  In particular, the second aspect of the present invention is such that, in the first aspect of the present invention, a decompressor or an electromagnetic expansion valve is connected to the second bypass circuit so that the flow of the refrigerant can be adjusted. The amount of heat provided for defrosting is adjusted according to the amount of frost, the amount of heat used for defrosting is minimized, and the maximum capacity can be exhibited for indoor heating.

  In particular, in the first invention, the third invention provides a decompressor between the refrigerant heater and the indoor heat exchanger, and operates the refrigerant heater as an evaporator. The heat absorption efficiency of the refrigerant is improved, and an efficient heat pump refrigeration cycle can be formed.

  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 pressure reducer 4, an outdoor heat exchanger 5, a first bypass circuit 6, a refrigerant heating two-way valve 7, a refrigerant heater 8, 2 bypass circuit 9, second bypass circuit defrosting two-way valve 10, second bypass circuit decompressor 11, first bypass circuit two-way valve 7, first bypass circuit decompressor 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.

  FIG. 2 is obtained by replacing the pressure reducer 4 in FIG. 1 with a two-way valve 4a.

  3 replaces the defrosting two-way valve 10 and the pressure reducer 11 of the second bypass circuit 9 in FIG. 1 with the pressure reducer 22, and moves the pressure reducer 12 of the first bypass circuit 6 to the main circuit. Is.

  Next, FIG. 4 is a control block diagram according to the present invention, and FIG. 5 is a time chart showing the behavior when the control is operated.

  In FIG. 4, 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.

  Here, the outdoor temperature is detected by the outdoor temperature detection means 60. If the outdoor temperature is equal to or higher than a predetermined temperature (for example, 1 ° C.), the decompressor 4 and the two-way defrosting valve 10 are closed to indoors. The outdoor refrigeration cycle is made independent, the outdoor fan is rotated, heat is exchanged between the outdoor air and the outdoor heat exchanger 5, and defrosting is performed by the heat of the outdoor air.

  Specifically, as shown in FIG. 5 (a), if the outdoor temperature is equal to or higher than a predetermined temperature (for example, 1 ° C.), the determination of the start of defrosting is made. Transition to heating operation by refrigerant heating operation. At this time, the refrigerant heating two-way valve is turned on and controlled in the opening direction.

  At this time, the defrosting two-way valve 10 is kept closed, and the heater heater 8 is turned on to perform the refrigerant heating operation. At this time, the expansion valve 4 is closed or close to being closed.

  The outdoor fan continues to operate.

  Since the four-way valve 2 continues heating, it does not switch even during defrosting in the heating circuit.

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

  Next, in step 3, the defrosting two-way valve 10 is kept closed, and the expansion valve 4 is closed or close to the closed state. The compressor 1 operates at a predetermined operating frequency.

  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.

  On the other hand, as shown in FIG. 5B, if the outdoor temperature is lower than a predetermined temperature (for example, 1 ° C.), the hot gas refrigerant is supplied to the outdoor side to perform defrosting. The outdoor fan 19 is stopped, the two-way defrosting valve 10 is opened in Step 3, and the outdoor fan 19 is also stopped.

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

  Further, the rotational speed of the indoor fan and the rotational speed of the outdoor fan may be fixed or variable.

  Further, the predetermined temperature (1 ° C. in this example) may vary depending on various conditions.

(Embodiment 2)
Next, Embodiment 2 will be described with reference to FIG. Parts similar to those of the first embodiment are omitted.

  The second embodiment is different from the first embodiment in that the defrosting two-way valve 10 is opened and the hot gas refrigerant is supplied to the outdoor heat exchanger 5 at the initial time and the final time of the step 3. It is a point to do.

  Since the initial frost in the defrosting operation is usually attached to the surface of the heat exchanger without any gaps, the efficiency can be improved even if outdoor air is applied to the heat exchanger and heat exchange is performed to dissolve the frost. bad.

  For this reason, the two-way valve 10 for defrosting is opened at the beginning of Step 3, the frost adhering to the outdoor heat exchanger is slightly peeled off or melted from the surface of the heat exchanger, and the frost is melted by heat exchange by the fan 19. Make it easy.

  And in the predetermined period of the end of step 3, in order to eliminate unmelted frost, the hot gas refrigerant is circulated to the outdoor heat exchanger.

  The outdoor fan 19 stops during the period when the two-way defrosting valve 10 is open, and operates during other periods. By these operations, the defrosting is completely completed.

  The heater part of the refrigerant heater may be of any shape and method as long as it is a heating element.

  In the present embodiment, one end of the connection portion of the first bypass circuit is between the four-way valve and the outdoor heat exchanger, but may be between the four-way valve and the compressor suction side. In this case, since the pressure loss of the refrigerant circulating from the refrigerant heater to the compressor decreases, it can be expected to improve the efficiency.

  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 an air conditioner according to an embodiment of the present invention Configuration diagram of an air conditioner according to an embodiment of the present invention Configuration diagram of an air conditioner according to an embodiment of the present invention Control block diagram of the present invention (A) is a time chart when the outdoor air temperature of the first embodiment of the present invention is 1 ° C. or higher. (B) is a time chart when the outdoor air temperature is similarly less than 1 ° C. Time chart when the outdoor temperature of the second embodiment of the present invention is 1 ° C. or higher 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 Defroster for frost 12 Depressurizer for refrigerant heating 13 Heater heater 14 Refrigerant passage pipe part 15 Heat storage part 16 Check valve 17 Indoor fan 18 Indoor unit 60 Outdoor temperature detection means

Claims (3)

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, between the indoor heat exchanger and the decompressor, the four-way valve, and the A first bypass circuit connecting between the outdoor heat exchangers, the four-way valve and the indoor heat exchanger, the decompressor and the outdoor heat exchanger, or the compressor A second bypass circuit connecting between the four-way valve and between the pressure reducer and the outdoor heat exchanger, a refrigerant heating two-way valve and a refrigerant heater in the first bypass circuit, A defrosting two-way valve, an outdoor temperature detecting means, an indoor fan for exchanging heat between the indoor heat exchanger and indoor air, an outdoor heat exchanger and outdoor air in the second bypass circuit; An outdoor fan that performs heat exchange, and detects the outdoor temperature when starting the defrosting operation. If the temperature detected by the stage is equal to or higher than the predetermined temperature, the vacuum vessel was substantially closed, and turn ON the refrigerant heater and-out the refrigerant heating two-way valve opens and the initial defrosting operation The two-way valve for defrosting is opened during a predetermined period at the end, the two-way valve for defrosting is closed except for the predetermined period at the initial stage and the end, and the two-way valve for defrosting is opened during the predetermined period. When the temperature detected by the outdoor temperature detecting means is less than a predetermined temperature , the operation of the outdoor fan is stopped and the outdoor fan is operated except for a predetermined period when the two-way valve for defrosting is opened . An air conditioner characterized in that the decompressor is substantially closed, the refrigerant heater is turned on, and the refrigerant heating two-way valve and the defrosting two-way valve are opened. The air conditioner according to claim 1, wherein a pressure reducer or an electromagnetic expansion valve is connected to the second bypass circuit to adjust a flow of the refrigerant. The air conditioner according to claim 1, wherein a decompressor is provided between the refrigerant heater and the indoor heat exchanger, and the refrigerant heater is operated as an evaporator.

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