Heat pump system for a vehicle

A heat pump system for a vehicle, comprising:

• a compressor configured to compress a refrigerant;
• a vehicle interior condenser connected to the compressor through a refrigerant line;
• a heat-exchanger connected to the vehicle interior condenser through the refrigerant line, and configured to condense or evaporate the refrigerant by heat-exchanging the supplied refrigerant with an ambient air;
• a first expansion valve connected to the heat-exchanger through the refrigerant line;
• an evaporator connected to the first expansion valve through the refrigerant line, and configured to evaporate the refrigerant by heat-exchanging the supplied refrigerant with the ambient air;
• a first connection line having a first end connected to the refrigerant line at a downstream end of the evaporator, and having a second end connected to the refrigerant line between the heat-exchanger and the first expansion valve;
• a chiller disposed on the first connection line, the chiller configured to adjust a temperature of the coolant by heat-exchanging the refrigerant introduced into the first connection line with a selectively introduced coolant;
• a second expansion valve disposed on the first connection line at an upstream end of the chiller;
• an ejector disposed on the refrigerant line between the evaporator and the compressor, the ejector configured to discharge the refrigerant at a pressure greater than a pressure of the introduced refrigerant;
• and
• a second connection line having a first end connected to the ejector, and having a second end connected to the refrigerant line between the heat-exchanger and the first expansion valve.