Heat pump system for a vehicle

A heat pump system for a vehicle, comprising:

• a compressor configured to compress a refrigerant;
• a front heating, ventilation, and air conditioning (HVAC) module configured to adjust a temperature of a front seat and including:
• an internal condenser,
• an evaporator connected to the compressor via a refrigerant line, and
• an opening/closing door configured to adjust ambient air having passed through the evaporator to be selectively introduced into the internal condenser at a time of cooling or heating a vehicle interior;
• a first heat-exchanger connected to the internal condenser via the refrigerant line;
• a first expansion valve provided on the refrigerant line between the first heat-exchanger and the evaporator;
• a first connection line including:
• a first end connected to the refrigerant line between the first heat-exchanger and the first expansion valve, and
• a second end connected to the refrigerant line between the evaporator and the compressor;
• a chiller provided on the first connection line and configured to exchange heat between a coolant and the refrigerant to adjust a temperature of the coolant;
• a second heat-exchanger provided on the refrigerant line and configured to exchange heat between the refrigerant having passed through the internal condenser or the first heat-exchanger and the refrigerant having passed through at least one of the evaporator and the chiller such that a condensation level is increased by increasing sub-cooling of the refrigerant;
• a rear connection line connected to the refrigerant line through at least one valve;
• and
• a rear HVAC module interiorly provided with a third heat-exchanger connected to the rear connection line and configured to adjust a temperature of a rear seat at the time of cooling or heating the vehicle interior.