An air conditioning system comprises a compressor (1), an outdoor heat exchanger (3), a first heat exchanger (101), a second heat exchanger (102) and at least two throttling devices, wherein the outdoor heat exchanger is a micro-passage heat exchanger and comprises a first inlet (31), a second inlet (32), an outlet (33), a distributing pipe (36), a collecting pipe (37), a flat pipe (38), a fin (39) and a distributor (34) which is located in the distributing pipe (36) and used for distributing a working medium, and a distribution small hole (35) is provided in the distributor (34); and the first inlet (31) is in direct communication with a distributing cavity (30) of the distributing pipe (36), while the second inlet (32) is in communication with the distributing cavity (30) through the distributing small hole (35) in the distributor (34).

Condensation occurs on an indoor fan. In an air conditioner of the present invention, an indoor heat exchanger includes an auxiliary heat exchanger 20 and a main heat exchanger 21 disposed leeward from the auxiliary heat exchanger 20. The auxiliary heat exchanger 20 is disposed forward of a front heat exchanger 21a of the main heat exchanger 21. In an operation in a predetermined dehumidification operation mode, a liquid refrigerant supplied to the auxiliary heat exchanger 20 all evaporates midway in the auxiliary heat exchanger 20. Then, the refrigerant having flowed through a superheat region of the auxiliary heat exchanger 20 flows through a portion of the front heat exchanger 21a which portion is located leeward from an evaporation region of the auxiliary heat exchanger 20.

When a fully-closable expansion valve is used, there is a possibility that the expansion valve is fully closed thereby to block a refrigerant circuit. In an air conditioner 1 of the present invention, an indoor heat exchanger 14 includes an auxiliary heat exchanger 20 and a main heat exchanger 21 disposed leeward from the auxiliary heat exchanger 20. In an operation in a predetermined dehumidification operation mode, a liquid refrigerant supplied to the auxiliary heat exchanger 20 all evaporates midway in the auxiliary heat exchanger 20, i.e., before reaching the outlet. Therefore, only an upstream partial area in the auxiliary heat exchanger 20 is an evaporation region, while an area downstream of the evaporation region in the auxiliary heat exchanger 20 is a superheat region. Further, an evaporation temperature sensor 30 which detects an evaporation temperature is disposed downstream of an expansion valve 13 in an outdoor unit 3.

An air conditioner includes a refrigerant circuit and a blower. A refrigerant flow path switching mechanism is configured to be switched to a first switching state to allow refrigerant to flow through a reheater, a first expansion valve, and a cooler in this order in the refrigerant circuit. The refrigerant flow path switching mechanism is configured to be switched to a second switching state to allow the refrigerant to flow through the reheater, the first expansion valve, and the cooler in this order in the refrigerant circuit. The reheater and the cooler are configured to allow air blown by the blower to pass through the cooler and then pass through the reheater during either of the first switching state and the second switching state.