JPH0820149B2 - Defrost control method during heating in an air conditioner - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a defrost control method for heating an air conditioner.

[0002]

2. Description of the Related Art Conventionally, in defrosting control during heating in an air conditioner, when a defrosting command is issued, defrosting immediately starts. Further, since the room temperature is not taken into consideration when starting the defrosting, when the defrosting command is issued, the defrosting is started regardless of the room temperature. Further, the defrosting method is often a reverse cycle method and has a structure in which a low-temperature refrigerant flows through the indoor heat exchanger during defrosting.

[0003]

Therefore, in the defrosting control during heating in the conventional air conditioner described above, the defrosting start timing is not taken into consideration, so the defrosting starts and ends frequently. There are problems that the operation of the air conditioner becomes unstable and that the room temperature drops significantly during defrosting. Further, in an air conditioner having an air cleaning function, the indoor blower is continuously operated even during defrosting, so that when a low-temperature refrigerant flows through the indoor heat exchanger, cold air blows out and the room temperature significantly decreases. there were.

The present invention solves the problems of the defrosting control during heating in the conventional air conditioner described above, stabilizes the operation of the air conditioner, and prevents the room temperature from significantly lowering during defrosting. An object of the present invention is to provide a defrosting control method during heating in an air conditioner that can be performed.

[0005]

In order to achieve the above object, in the defrosting control method during heating in the air conditioner of the first aspect of the invention, a defrosting temperature controller for detecting frost forms a defrosting command. Defrosting is started when the set time of the defrosting interval timer has elapsed after output, and the defrosting command from the defrosting temperature controller is released, or the defrosting timer is started after defrosting is started. It is characterized in that the defrosting is finished when only the set time of has passed. Further, in the defrosting control method during heating in the air conditioner of the second aspect of the present invention, the defrosting temperature controller that detects frost formation outputs a defrosting command and then the set time of the defrosting interval timer elapses. Or, when the room temperature reaches the upper limit set temperature of the indoor temperature controller, defrosting is started and the defrosting command from the defrosting temperature controller is released, or defrosting is started and then defrosting is started. It is characterized in that the defrosting is terminated when the set time of the frost timer has elapsed. The defrosting control method during heating in the air conditioner of the third aspect of the invention is the defrosting control method during heating in the air conditioner of the first aspect or the second aspect of the invention, wherein the discharge pipe of the compressor and the outdoor side are included. A bypass circuit is connected to the outlet of the heat exchanger, and an electromagnetic valve for opening and closing the bypass circuit is provided. When defrosting is started, the electromagnetic valve is opened, and the discharge gas is discharged from the discharge side of the compressor to the outdoor side. The feature is that hot gas defrosting is performed by bypassing directly to the heat exchanger.

[0006]

In the first aspect of the invention, the temperature of the inlet pipe of the outdoor heat exchanger decreases due to the decrease of the outside air temperature and the room temperature during heating, and when the temperature falls below the set temperature, the contact point of the defrosting temperature controller closes and the defrosting is performed. Output frost command. Even if the defrosting temperature controller outputs the defrosting command, defrosting does not start immediately and the defrosting temperature controller outputs the defrosting command and the defrosting interval timer has elapsed for the set time. By starting defrosting, the start and end of defrosting do not occur frequently, the operation of the air conditioner is stabilized, and it is possible to suppress a decrease in room temperature due to defrosting. By starting defrosting, the defrosting command from the defrosting temperature controller is released, or by ending the defrosting when the set time of the defrosting timer has elapsed after starting defrosting, It is possible to suppress a decrease in room temperature due to defrosting. In the case of the second aspect of the present invention, further, after the defrosting temperature controller that detects frost formation outputs a defrosting command, only the set time of the defrosting interval timer elapses, or the room temperature is the upper limit of the indoor temperature controller. By starting defrosting when the set temperature is reached, defrosting can be efficiently performed while suppressing a decrease in room temperature due to defrosting. In the case of the third aspect of the present invention, further, by bypassing the discharge gas from the discharge side of the compressor directly to the outdoor heat exchanger and performing hot gas defrosting, even if the indoor blower is continuously operated during defrosting. It is possible to prevent the cold air from being blown out, and it is possible to suppress a decrease in room temperature due to defrosting.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A defrost control method for heating an air conditioner of the present invention will be described below with reference to the illustrated embodiments. The indoor heat exchanger 2 is mounted on the ceiling of the air-conditioned room 1 having a required size.
1, the indoor unit 2 incorporating the indoor blower 22 and the expansion device 23, and the filter unit 3 having the indoor cleaning filter 31 are provided. Compressor 4 outdoors
1, four-way switching valve 42, outdoor heat exchanger 43, throttle device 4
The outdoor unit 4 incorporating the 4 and the accumulator 45 is provided. Indoor unit 2 and outdoor unit 4
Are connected by a refrigerant pipe 11 and an electric wiring 12.

Air conditioning of the air conditioning room 1 is performed by turning on the switch of the operation panel 5 and setting the room temperature controller 6 to the required room temperature. The air conditioning in the air conditioning room 1 is guided by the blower 22 of the indoor unit 2 from the suction grill 7 to the ceiling by the duct 8 and passes through the indoor heat exchanger 21 of the indoor unit 2 to perform heat exchange, and the filter unit 3 The air is passed through the filter 31 and is blown out into the air-conditioning chamber 1 through the air outlet 32 to cool or heat the air.
When performing air cleaning, the outside air is taken in through the outside air intake 9, and the inside of the room is kept at a positive pressure by the positive pressure damper 10.

The temperature of the air-conditioned room 1 is controlled by the room temperature controller 6
Thus, the compressor 41 of the outdoor unit 4 is automatically started and stopped, and the four-way switching valve 42 is operated to perform cooling and heating. The indoor temperature controller 6 is of a three-position operation type, and switches to a cooling or heating circuit according to the degree of increase or decrease of the indoor temperature with respect to a set value and adjusts the temperature respectively.

In operation, when the room temperature is significantly lower than the set value of the room temperature controller 6, the heating side is turned on, the four-way switching valve 42 is opened to the heating side, and the compressor 41 is operated. Perform heating operation. When the outside air temperature and the room temperature are operating at low values, the surface temperature of the pipe 48 at the inlet of the outdoor heat exchanger 43 decreases, and when the defrosting temperature controller 47 detects frosting, it outputs a defrosting command. . Even if the defrosting temperature controller 47 outputs the defrosting command, defrosting does not start immediately, and the defrosting temperature controller 47 that detects frost formation outputs the defrosting command and then the defrosting interval timer 51. The operation is continued as it is until the set time of (1) or the room temperature reaches the upper limit set temperature of the indoor temperature controller 6.

After the defrosting temperature controller 47 outputs the defrosting command, only the set time of the defrosting interval timer 51 elapses, or the room temperature reaches the upper limit set temperature of the indoor temperature controller 6 and the control circuit is opened. The relay 13 operates to start defrosting while the four-way switching valve 42 remains unchanged. In this way, the defrosting temperature controller 47 that detects frost formation outputs the defrosting command, and then the set time of the defrosting interval timer 51 elapses, or the room temperature reaches the upper limit set temperature of the indoor temperature controller 6. When defrosting is started, defrosting can be efficiently performed while suppressing a decrease in room temperature due to defrosting. At the same time when defrosting is started, the defrosting timer 52 operates. The solenoid valve 4 of the bypass circuit of the outdoor unit 4 during defrosting
9, the discharge gas of the compressor 41 is directly bypassed to the outlet of the outdoor heat exchanger 43 of the outdoor unit 4, and the frost attached to the outdoor heat exchanger 43 is removed by the hot gas. At this time, since a low-temperature refrigerant does not flow into the heat exchanger 21 of the indoor unit 2, even if the indoor blower 22 is continuously operated during defrosting, it is possible to prevent blowout of cold air and to prevent defrosting. A decrease in room temperature can be suppressed.

Thereafter, the frost is removed and the surface temperature of the pipe 48 at the inlet of the heat exchanger 43 rises, and the defrosting command from the defrosting temperature controller 47 is canceled or after the defrosting is started. When the set time of the defrost timer 42 has elapsed, the defrost is finished.

[0013]

According to the first aspect of the present invention, defrosting does not start and end infrequently, the operation of the air conditioner is stable, and the decrease in room temperature due to defrosting can be suppressed.

According to the second aspect of the present invention, the start of defrosting,
It does not end frequently, the operation of the air conditioner is stable, and defrosting can be efficiently performed while suppressing a decrease in room temperature due to defrosting.

Further, according to the third aspect of the present invention, even if the indoor side blower is continuously operated during defrosting, cold air can be prevented from being blown out, and a decrease in room temperature due to defrosting can be suppressed.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing an example of an air conditioner used in the method of the present invention.

FIG. 2 is a circuit diagram of the same refrigerant.

[Explanation of symbols]

 1 Air Conditioning Room 2 Indoor Unit 3 Filter Unit 4 Outdoor Unit 5 Operation Panel 6 Indoor Temperature Controller 7 Suction Grill 8 Duct 9 OA Intake 10 Positive Pressure Damper 11 Refrigerant Piping 12 Electrical Wiring 13 Auxiliary Relay 21 Indoor Heat Exchanger 22 Blower 23 Throttle device 24 Strainer 31 Filter 32 Air outlet 41 Compressor 42 Four-way switching valve 43 Outdoor heat exchanger 44 Throttle device 45 Accumulator 46 Strainer 47 Defrosting temperature controller 48 Outdoor heat exchanger inlet pipe 49 Solenoid valve for bypass 51 Defrost Interval Timer 52 Defrost Timer

Claims (3)

[Claims] 1. A defrosting temperature controller (4) for detecting frost formation.
7) outputs the defrost command, the defrost interval timer (5
Whether defrosting is started when the set time of 1) has elapsed and the defrosting command from the defrosting temperature controller (47) is released,
Alternatively, the defrosting control method during heating in the air conditioner, which is characterized in that the defrosting is ended when the set time of the defrosting timer (42) has elapsed since the defrosting was started. 2. A defrosting temperature controller (4) for detecting frost formation.
7) outputs the defrost command, the defrost interval timer (5
Defrosting is started when the set time of 1) elapses or when the room temperature reaches the upper limit set temperature of the indoor temperature controller (6), and the defrosting command from the defrosting temperature controller (47) is issued. Defrost timer (42) after being released or starting defrost
The defrosting control method at the time of heating in the air conditioner, characterized in that the defrosting is ended when only the set time of is elapsed. 3. A defroster is provided by connecting a bypass circuit between the discharge pipe of the compressor (41) and the outlet of the outdoor heat exchanger (43) and providing an electromagnetic valve (49) for opening and closing the bypass circuit. When starting, the solenoid valve (49) is opened, the discharge gas is directly bypassed from the discharge side of the compressor (41) to the outdoor heat exchanger (43), and hot gas defrosting is performed. The defrosting control method at the time of heating in the air conditioner according to claim 1 or 2.