Multi-split air conditioning system

The invention relates to a multi-split air conditioning system. A compressor, an outdoor heat exchanger and an indoor heat exchanger form a connection loop through two four-way valves, electronic expansion valves, electromagnetic valves, wherein a terminal a of a first four-way valve is connected with the refrigerant outlet of the compressor; the terminal d of the first four-way valve is connected with the terminal w of a second four-way valve by virtue of a check valve; the terminal c of the first four-way valve is connected with the terminal y of the second four-way valve in parallel and then is connected with the refrigerant inlet of the compressor by virtue of a gas-liquid separator; the terminal w of the second four-way valve is connected with the refrigerant outlet of the compressor through a first electromagnetic valve; the terminal x of the second four-way valve is sequentially connected with the outdoor heat exchanger, a high pressure liquid storage tank, a second electromagnetic valve, a second electronic expansion valve, an indoor unit electronic expansion valve and the terminal s1 of the indoor heat exchanger; and the terminal s2 of the indoor heat exchanger is connected with the terminal b of the first four-way valve. The multi-split air conditioning system disclosed by the invention is mainly applied to a heat pump air conditioning hot water system and has an ice storage function. The multi-split air conditioning system disclosed by the invention can save more energy, and has high working efficiency and wider practical range.