JPH05187685A - Controller for air conditioner - Google Patents

Abstract

PURPOSE:To maintain comfortable room heating environment by effectively defrosting by regulating a setting time of a timer and by early recovering a decrease in a room temperature. CONSTITUTION:If a timer 15 is not up, a controller 9 adds a previously set constant temperature to a defrost ending temperature to newly set a defrost ending temperature. A defrosting operation is continued until a temperature of a heat exchanger exceeds the newly set defrosting temperature so as to completely defrost. Further, the previously set constant temperature is added to an indoor set temperature to newly set an indoor set temperature. Then, rise of the indoor temperature after the end of the defrosting is accelerated thereby to early recover a decrease in a room temperature during the defrosting operation. If the timer 15 is up, it can be recovered to a room heating operation without altering the defrost ending temperature and the indoor set temperature. Thus, comfortable room heating environment can be maintained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to defrosting operation control for an air conditioner.

[0002]

2. Description of the Related Art Conventionally, in a heat pump type air conditioner, after the heating is started and the compressor is operated for a certain integration time, the temperature of the outdoor heat exchanger is detected and a predetermined value (for example, −10 ° C.) is detected.
When it is less than C), it is determined that frost has formed on the outdoor heat exchanger and the defrosting operation is controlled. The defrosting operation is
The high-temperature refrigerant gas from the compressor is switched by the four-way valve to flow to the outdoor heat exchanger, heats the outdoor heat exchanger, melts frost, and discharges it to the outside of the machine. When the value exceeds a value (for example, 10 ° C), it is determined that all frost has been removed, and the four-way valve is switched to return to the heating operation. However, when the outdoor heat exchanger has a large amount of frost and the outside air temperature is low (for example, 0 ° C or lower), the outdoor heat exchanger and its surroundings are kept at a low temperature even during the defrosting operation, and the outdoor heat exchanger is kept outside. Water drops dripping from the heat exchanger do not flow out from the drainage port of the bottom plate, and when the heating operation is restored, the outdoor heat exchanger cools and freezes the ice, lowers the temperature of the outdoor heat exchanger, and removes it again early. The frost operation has been repeated, which may cause a decrease in the indoor temperature, so that the comfortable heating operation cannot be continued.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems of the prior art, and is an air conditioner capable of reliably removing frost on the outdoor heat exchanger even when the outside air temperature is low. It is intended to provide a control device for a machine.

[0004]

In order to achieve the above object, the control device is provided with a timer for counting the time from the end of defrosting to the start of the next defrosting, and the time until the start of the next defrosting is a predetermined value. If it is less than, the defrosting end temperature is increased by a predetermined value to continue the defrosting operation, and the indoor set temperature is increased by a predetermined value after the defrosting is finished to recover the decrease in the indoor temperature during defrosting. I did it.

[0005]

According to the above configuration, in the control device of the air conditioner in which the defrosting operation is controlled by the temperature of the outdoor heat exchanger, the time from when the defrosting operation ends to when the next defrosting operation starts When a time to start the next defrosting operation is less than a predetermined value, a timer that counts the defrosting operation is performed to increase the defrosting end temperature by a predetermined value and continue the defrosting operation to ensure defrosting. In addition, the indoor set temperature is increased by a predetermined value at the end of the defrosting operation, so that the decrease in the indoor temperature due to the extension of the defrosting operation time is quickly recovered.

[0006]

Embodiments of the present invention will be described in detail with reference to the accompanying drawings by taking a forced defrosting method using a refrigerant hot gas as an example. FIG. 1 is a refrigerant circuit diagram showing the configuration of the present invention. The compressor 1 returns to the four-way valve 2 from a discharge side, a four-way valve 2, an indoor heat exchanger 3, an expansion valve 4, an outdoor heat exchanger 5, A refrigerant circuit reaching the compressor 1 is formed, and the indoor side heat exchanger 3 and the outdoor side heat exchanger 5 are in close proximity to the indoor side blower 6 and the outdoor side blower 7.
Are stored in the housings of the indoor unit and the outdoor unit, respectively. The figure shows the heating operation state, and the refrigerant gas compressed to high temperature and high pressure by the compressor 1 is sent to the indoor heat exchanger 3 by the four-way valve 2 as shown by the arrow, and the indoor blower 6 performs the indoor heat exchange. The heat exchange is performed with the indoor air flowing between the coolers 3, and the cooled refrigerant gas is liquefied and passes through the expansion valve 4, enters the outdoor heat exchanger 5 and is vaporized, and is vaporized from the outdoor air by the outdoor blower 7. It takes heat and returns to the suction side of the compressor 1 via the four-way valve 2. An outdoor heat exchanger temperature sensor 8 that detects the temperature of the outdoor heat exchanger 5 is arranged on the inlet side of the outdoor heat exchanger 5. When the heating operation is continued in a state where the outdoor air temperature is low, the temperature of the outdoor heat exchanger 5 becomes lower than the outdoor air temperature and frost is formed on the outdoor heat exchanger 5, and the outdoor heat exchanger 5 grows due to the change in the outdoor air temperature. In order to reduce the heat exchange efficiency of the exchanger 5, it is necessary to defrost periodically.

FIG. 2 is a control block diagram.
A setting input circuit 10, an indoor temperature sensor 11, and an outdoor heat exchanger temperature sensor 8 are connected as inputs, and the control unit 9 has an A / A
A D converter 12, a comparison circuit 13, a memory 14, a timer 15 and the like are provided, and the indoor blower 6, the outdoor blower 7, the compressor 1 and the four-way valve 2 are connected as outputs. Setting input circuit
The indoor set temperature, the defrost start temperature and defrost end temperature of the outdoor heat exchanger 5, the set time of the timer 15, the control conditions of the output side device, and the like are input from 10 and stored in the memory 14. In this state, the control unit 9 starts the operation of the compressor 1 and at the same time the operation of the indoor side blower 6 and the outdoor side blower 7, and the signal detected by the indoor temperature sensor 11 is the A / D converter 12
The output side device is controlled so as to comply with the control condition by being compared with the set value stored in the memory 14 by being taken into the comparison circuit 13 via.

FIG. 3 is a flow chart of the present invention, in which the outdoor heat exchanger temperature sensor 8 has passed a certain time since the start of heating operation.
When the outdoor heat exchanger temperature (hereinafter referred to as heat exchanger temperature) detected by the temperature falls below the preset defrost start temperature Tr2 (for example, -10 ° C), the outdoor heat exchanger 5 is frosted. It is determined that the indoor side blower 6 and the outdoor side blower 7 are stopped, the four-way valve 2 is switched to the cooling side, and defrosting of the outdoor side heat exchanger 5 is started. Exceeds the preset defrosting end temperature Tr1 (for example, 5 ° C) (2
1) The four-way valve 2 is switched to return to heating operation (22). At the same time when the heating operation is started, the control unit 9
The timer 15 is set to the preset defrosting time (23). When the heat exchanger temperature falls below the defrosting start temperature Tr2 again in this state (24), the operation immediately shifts to the defrosting operation (25), but when the timer 15 has not timed up (26 ), The control unit 9 adds the preset constant temperature A ° C to the defrosting end temperature Tr1 to newly add the defrosting end temperature T.
r1 (27), the defrosting operation is continued until the heat exchanger temperature exceeds the newly set defrosting end temperature Tr1 (28), and the indoor set temperature Ts1 is further set. Preliminarily set constant temperature B ° C is added to newly set the room temperature (29), the rise of the room temperature after defrosting is accelerated, and the decrease in room temperature during defrosting operation is quickly recovered. I am trying to let you. When the timer 15 is up (26), the heating operation is restored (30, 31) without changing the defrosting end temperature and the indoor set temperature.
The same applies to the method of defrosting the outdoor heat exchanger by energizing the heater attached to the outdoor heat exchanger, or the method of defrosting the outdoor heat exchanger by stopping the compressor during defrosting. The effect can be improved.

[0009]

As described above, according to the present invention, when the defrosting is not completely completed at the end of the defrosting operation and the defrosting operation is performed again in a short time after the heating operation is restored, the defrosting operation is completed. By increasing the temperature by a certain value and delaying the defrost recovery,
Defrosting can be completed completely at the end of defrosting operation, and the decrease in room temperature during this time can be quickly recovered by raising the indoor set temperature after heating operation by a certain value, which is comfortable. The heating environment can be maintained.

[Brief description of drawings]

FIG. 1 is a refrigerant circuit diagram showing the configuration of the present invention.

FIG. 2 is a control block diagram of the same.

FIG. 3 is the same flowchart.

[Explanation of symbols]

 1 compressor 2 4-way valve 3 indoor heat exchanger 4 expansion valve 5 outdoor heat exchanger 6 indoor blower 7 outdoor blower 8 outdoor heat exchanger temperature sensor 9 controller 10 setting input circuit 11 indoor temperature sensor 12 A / D converter 13 Comparison circuit 14 Memory 15 Timer

Claims (1)

[Claims] 1. The temperature of the outdoor heat exchanger is detected by the outdoor heat exchanger temperature sensor during the heating operation of the air conditioner, and defrosting is started when the detected temperature reaches a predetermined defrosting start temperature. In the control device of the air conditioner that performs defrosting of the outdoor unit so as to return to the heating operation when the detected temperature reaches the defrosting end temperature, in the control device, from the defrosting end to the next defrosting start A timer that counts time is provided, and when the time until the start of the next defrost is less than a predetermined value, the defrost operation is continued by increasing the set value of the defrost end temperature by a predetermined value, and after the defrost finishes. An air conditioner control device, characterized in that the indoor set temperature is raised by a predetermined value to recover the decrease in the indoor temperature during defrosting.