JPH07174441A - Defrost controller for air conditioner - Google Patents

Abstract

PURPOSE:To shorten a quiescent time of a heating operation by abruptly lowering a high pressure of refrigerant at the time of finishing a defrosting operation, and eliminating a refrigerant flowing sound to an indoor unit even if switching of a four-way valve to a heating operation side is early advanced. CONSTITUTION:At the time of frosting being generated in an outdoor unit, an operation of a compressor 1 is stopped, and an outdoor fan 7 is stopped by a controller 8. After a predetermined time is elapsed, a four-way valve 2 is switched to defrosting, and the operation of the compressor 1 is started. Refrigerant compressed to a high temperature and a high pressure is fed to an outdoor heat exchanger 6 and defrosted. The refrigerant cooled by the outdoor exchanger is pressure-reduced by a capillary tube 5, and returned to the compressor through an indoor heat exchanger 3 and the valve. The operation of the compressor is stopped upon finishing of defrosting, the fan is simultaneously rotated to cool the outdoor exchanger, thereby lowering a pressure of the refrigerant, and a pressure difference between a high pressure side and a low pressure side is abruptly lowered. After a predetermined time is elapsed, the valve is switched to heating, and the operation of the compressor is restarted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat pump type air conditioner, which reduces a switching noise of a four-way valve at the end of defrosting.

[0002]

2. Description of the Related Art When a four-way valve is switched to defrost frost attached to an outdoor heat exchanger during heating operation of a heat pump type air conditioner and to return to heating operation at the end of defrosting operation, high pressure side and low pressure side Due to the pressure difference between the two sides, the refrigerant abruptly flows into the low pressure side, that is, the indoor unit side, so that annoying refrigerant flow noise is generated. Conventionally, in order to reduce this annoying refrigerant inflow noise, for example, a time is provided between the end of the defrosting operation and the switching of the four-way valve, and the four-way valve is switched in the state where the pressure difference becomes small. Therefore, the rest time of heating is the time required for defrosting plus the time for reducing this pressure difference. This increases the number of operation pauses, which is an obstacle to comfortable heating operation.

[0003]

The downtime of the heating operation is the time required for defrosting plus the time for reducing the pressure difference of the refrigerant. The present invention pays attention to this point, and after the defrosting operation is completed, the lowering speed of the high pressure of the refrigerant is accelerated so that the refrigerant inflow noise into the indoor unit does not occur even if the switching of the four-way valve is accelerated, and thus the heating operation is performed. The purpose is to shorten the downtime and to provide comfortable heating.

[0004]

In order to solve the above problems, the present invention forms a refrigeration cycle by sequentially connecting a compressor, a four-way valve, an indoor heat exchanger, a capillary tube, and an outdoor heat exchanger, In the one that performs cooling, heating, defrosting operation, etc. by switching the four-way valve, at the end of the defrosting operation, the outdoor fan is rotated by stopping the operation of the compressor and blown to the outdoor heat exchanger for a predetermined time. After the lapse of time, the four-way valve was switched to the heating operation side to configure the defrost control device for the air conditioner.

[0005]

With the above-described structure, the defrosting control device for an air conditioner according to the present invention starts blowing air by the outdoor fan at the same time when the compressor is stopped when the defrosting operation ends. As a result, heat is quickly radiated from the outdoor heat exchanger, the high-pressure pressure drops faster, and the time required to reduce the pressure difference between the high-pressure side and the low-pressure side is shortened. No harsh refrigerant inflow noise is generated.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a defrosting control device for an air conditioner according to the present invention will be described in detail below with reference to the drawings. FIG. 1 is a refrigerant circuit diagram showing an embodiment of a defrost control device for an air conditioner according to the present invention. In the figure, 1 is a compressor, 2 is a four-way valve, 3 is an indoor heat exchanger, 4 is an indoor fan, 5 is a capillary tube, 6 is an outdoor heat exchanger, 7 is an outdoor fan, and 8 is a controller. During heating operation, the refrigerant compressed to high temperature and high pressure by the compressor 1 is sent to the indoor heat exchanger 3 through the four-way valve 2 switched to "heating" by the signal from the control unit 8 as shown by the solid arrow, The indoor heat exchanger 3 exchanges heat with the air sucked from the room by the indoor fan 4 that rotates based on the signal from the control unit 8, and the refrigerant cooled by this heat exchange is decompressed by the capillary tube 5, The vaporized gas enters the outdoor heat exchanger 6, and heat is exchanged with the outdoor air by the outdoor heat exchanger 6 by blowing air from the outdoor fan 7 that rotates by a signal from the control unit 8, and passes through the four-way valve 2 and the compressor. It circulates in the route returning to the suction side of 1.

The controller 8 determines the start of the defrosting operation based on, for example, the cumulative heating operation time of the compressor 1, the difference between the indoor heat exchanger temperature and the indoor temperature, and the like. Then, as shown in the time chart of FIG. 2, the control unit 8 temporarily stops the operation of the compressor 1 (), and stops the rotation of the outdoor fan 7. Then, after switching the four-way valve 2 to "defrost", the compressor 1 is controlled to start operation (), and the high-temperature and high-pressure refrigerant from the compressor 1 is passed through the four-way valve 2 to generate outdoor heat as indicated by a dotted arrow. Defrost is sent to the exchanger 6. The refrigerant cooled by heat exchange in the outdoor heat exchanger 6 is decompressed in the capillary tube 5 and returns to the suction side of the compressor 1 via the indoor heat exchanger 3 and the four-way valve 2.

Upon completion of defrosting, the controller 8 stops the operation of the compressor 1 (), and at the same time, sends a signal to the outdoor fan 7 to start blowing air to the outdoor heat exchanger 6. The temperature of the outdoor heat exchanger 6 is rapidly lowered by this air blowing, and
The high-pressure refrigerant accumulated in the outdoor heat exchanger 6 is condensed,
The pressure drops. When the time a set as the time required to reduce the pressure of the refrigerant has elapsed (), a signal is output from the control unit 8, the four-way valve 2 is switched to "heating", and the operation of the compressor 1 is started.

[0009]

As described above, according to the defrosting control device for an air conditioner of the present invention, when the defrosting operation is completed, the outdoor fan is simultaneously rotated to lower the temperature of the outdoor heat exchanger. Since the pressure drop of the refrigerant on the high-pressure side is promoted, the pressure difference between the high-pressure side and the low-pressure side decreases rapidly, which allows the indoor heat exchanger to be switched even if the "heating" switching of the four-way valve for returning to heating operation is accelerated. Since no annoying refrigerant inflow noise is generated, the downtime of heating operation can be shortened, comfortable heating can be performed, and it is particularly effective when the outside air temperature is low.

[Brief description of drawings]

FIG. 1 is a refrigerant circuit diagram showing an embodiment of a defrost control device for an air conditioner according to the present invention.

FIG. 2 is a time chart for explaining the on / off timings of the compressor and the outdoor fan.

[Explanation of symbols]

 1 Compressor 2 Four-way valve 3 Indoor heat exchanger 4 Indoor fan 5 Capillary tube 6 Outdoor heat exchanger 7 Outdoor fan 8 Control part

Claims (1)

[Claims] 1. A refrigeration cycle is constructed by sequentially connecting a compressor, a four-way valve, an indoor heat exchanger, a capillary tube, and an outdoor heat exchanger, and cooling, heating, defrosting operation, etc. are performed by switching the four-way valve. When the defrosting operation is completed, the outdoor fan is rotated by stopping the operation of the compressor to blow air to the outdoor heat exchanger, and after a lapse of a predetermined time, the four-way valve is switched to the heating operation side. A defrost control device for an air conditioner.