An air conditioner system comprising: a compressor configured to compress refrigerant; a condenser configured to condense the compressed refrigerant in the compressor; an expander configured to expand the condensed refrigerant in the condenser; an evaporator configured to evaporate the expanded refrigerant in the expander; a flow switching unit configured to control a direction of refrigerant flow based on an operation mode of the system, wherein the operation mode comprises a cooling or warming operation mode; a gas-liquid separator configured to receive the evaporated refrigerant from the flow switching unit; and a bypass pipeline configured to guide the evaporated refrigerant from the evaporator to the condenser, wherein the bypass pipeline comprises: a fist bypass pipe configured to guide at least partially the evaporated refrigerant from the evaporator to the condenser; a second bypass pipe (170; 173, 174) connected to the first bypass pipe and configured to allow heat exchange between refrigerant in the condenser and refrigerant therein; and a third bypass pipe connected to the second bypass pipe (170; 173, 174) and configured to guide the refrigerant from the second bypass pipe (170; 173, 174) to outside of the condenser, wherein the system further comprises: a gas-liquid separation input pipe (142, 161) extending from the flow switching unit to the gas-liquid separator and configured to guide the evaporated refrigerant to the gas-liquid separator; a divider coupled to the first bypass pipe; a gas-liquid separation output pipe (162, 132) configured to guide vapor-phase refrigerant separated in the gas-liquid separator to the compressor, wherein the gas-liquid separation output pipe (162, 132) comprises a combiner coupled to the third bypass pipe, characterised in that said divider is disposed at the gas-liquid separation input pipe (142,161). a compressor configured to compress refrigerant; a condenser configured to condense the compressed refrigerant in the compressor; an expander configured to expand the condensed refrigerant in the condenser; an evaporator configured to evaporate the expanded refrigerant in the expander; a flow switching unit configured to control a direction of refrigerant flow based on an operation mode of the system, wherein the operation mode comprises a cooling or warming operation mode; a gas-liquid separator configured to receive the evaporated refrigerant from the flow switching unit; and a bypass pipeline configured to guide the evaporated refrigerant from the evaporator to the condenser, wherein the bypass pipeline comprises: a fist bypass pipe configured to guide at least partially the evaporated refrigerant from the evaporator to the condenser; a second bypass pipe (170; 173, 174) connected to the first bypass pipe and configured to allow heat exchange between refrigerant in the condenser and refrigerant therein; and a third bypass pipe connected to the second bypass pipe (170; 173, 174) and configured to guide the refrigerant from the second bypass pipe (170; 173, 174) to outside of the condenser, wherein the system further comprises: a gas-liquid separation input pipe (142, 161) extending from the flow switching unit to the gas-liquid separator and configured to guide the evaporated refrigerant to the gas-liquid separator; a divider coupled to the first bypass pipe; a gas-liquid separation output pipe (162, 132) configured to guide vapor-phase refrigerant separated in the gas-liquid separator to the compressor, wherein the gas-liquid separation output pipe (162, 132) comprises a combiner coupled to the third bypass pipe, characterised in that said divider is disposed at the gas-liquid separation input pipe (142,161). a fist bypass pipe configured to guide at least partially the evaporated refrigerant from the evaporator to the condenser; a second bypass pipe (170; 173, 174) connected to the first bypass pipe and configured to allow heat exchange between refrigerant in the condenser and refrigerant therein; and a third bypass pipe connected to the second bypass pipe (170; 173, 174) and configured to guide the refrigerant from the second bypass pipe (170; 173, 174) to outside of the condenser, wherein the system further comprises: a gas-liquid separation input pipe (142, 161) extending from the flow switching unit to the gas-liquid separator and configured to guide the evaporated refrigerant to the gas-liquid separator; a divider coupled to the first bypass pipe; a gas-liquid separation output pipe (162, 132) configured to guide vapor-phase refrigerant separated in the gas-liquid separator to the compressor, wherein the gas-liquid separation output pipe (162, 132) comprises a combiner coupled to the third bypass pipe, characterised in that said divider is disposed at the gas-liquid separation input pipe (142,161). a gas-liquid separation input pipe (142, 161) extending from the flow switching unit to the gas-liquid separator and configured to guide the evaporated refrigerant to the gas-liquid separator; a divider coupled to the first bypass pipe; a gas-liquid separation output pipe (162, 132) configured to guide vapor-phase refrigerant separated in the gas-liquid separator to the compressor, wherein the gas-liquid separation output pipe (162, 132) comprises a combiner coupled to the third bypass pipe, characterised in that said divider is disposed at the gas-liquid separation input pipe (142,161).