Abstract: A multi-outdoor unit parallel type non-reversing defrosting system, which includes an indoor heat exchanger and three or more outdoor units arranged in parallel. The outdoor units each include a compressor, a four-way valve, an outdoor heat exchanger, a first solenoid valve, and a bypass branch. Two ends of the bypass branch are respectively in bypass connection with a pipeline between the four-way valve and the outdoor heat exchanger and a pipeline between the first solenoid valve and the indoor heat exchanger. The bypass branch is provided with a second solenoid valve configured to control connection and disconnection of the bypass branch. When it is monitored that any outdoor unit is abnormal in frosting, the outdoor units which are not frosted are correspondingly distributed and started as required on the basis of a current heating energy requirement A of the indoor heat exchanger.

Abstract: An air conditioner defrosting method. In the air conditioner’s heating process, after the end of every defrosting procedure, the temperature of the outdoor heat exchanger coil and the time used over the course of the defrosting procedure can be measured and recorded. The defrosting situation of the air conditioner is reflected, and an initial determination of whether there is frost accumulation is made. After the initial determination, the air conditioner continues carrying out the heating procedure, and when specific conditions are met, it carries out a third defrosting procedure. When second determination results indicate that there is frost accumulation, the frost accumulation problem is deemed to be quite severe with a risk of icing up, and it is necessary to conduct forced intervention and carry out forced defrosting steps.

Abstract: A multi-outdoor unit parallel type non-reversing defrosting system, which includes an indoor heat exchanger and three or more outdoor units arranged in parallel. The outdoor units each include a compressor, a four-way valve, an outdoor heat exchanger, a first solenoid valve, and a bypass branch. Two ends of the bypass branch are respectively in bypass connection with a pipeline between the four-way valve and the outdoor heat exchanger and a pipeline between the first solenoid valve and the indoor heat exchanger. The bypass branch is provided with a second solenoid valve configured to control connection and disconnection of the bypass branch. When it is monitored that any outdoor unit is abnormal in frosting, the outdoor units which are not frosted are correspondingly distributed and started as required on the basis of a current heating energy requirement A of the indoor heat exchanger.