An air conditioner system including a compressor, a condenser, an expander, an evaporator, and a bypass pipeline that guides the evaporated refrigerant from the evaporator to the condenser, wherein the bypass pipeline includes: a first bypass pipe configured to guide at least some of the evaporated refrigerant from the evaporator to the condenser; a second bypass pipe attached to the first bypass pipe to allow heat exchange between refrigerant in the condenser and refrigerant therein; and a third bypass pipe coupled to the second bypass pipe to guide the refrigerant from the second bypass pipe out of the condenser.