AIR CONDITIONER CAPABLE OF SIMULTANEOUS DEFROSTING AND HEATING OPERATIONS, AND OUTDOOR UNIT FOR AIR CONDITIONER HAVING SELF-DEFROSTING CYCLE FOR REDUCING NOISE CAUSED BY INFLOW OF A REFRIGERANT

摘要

PURPOSE: An air conditioner capable of simultaneous defrosting and heating operations, and an outdoor unit for an air conditioner having a self-defrosting cycle are provided to prevent generation of a noise due to inflow of a refrigerant to an indoor unit in defrosting operation. CONSTITUTION: Plural indoor units(11) are installed. Compressors(23) compress a refrigerant. An outdoor heat exchanger(33) exchanges heat of the refrigerant. A four-way valve(31) is arranged at discharge sides of the compressors for switching a passage of the refrigerant. An accumulator(35) provides gaseous refrigerant to suction sides of the compressors. In defrosting, a bypass passage(51) is connected to have one end communicated with an outlet of the outdoor heat exchanger, and the other end communicated with a suction side of the accumulator. An outdoor expansion device(53) is arranged in the bypass passage. An electric heater(55) is arranged on the lower outdoor expansion device. A first main refrigerant pipe(47) connects outlet sides of outdoor units(22a,22b) in association with a flow direction of the refrigerant. A second main refrigerant pipe(48) is installed to flow the refrigerant to be moved into each outdoor unit via the indoor units.