HEAT PUMP SYSTEM FOR A VEHICLE

In order to efficiently perform heating of a vehicle interior in a state in which the external temperature is low and heat generated by a heating element is not sufficient in an early stage of driving the vehicle, a heat pump system for a vehicle is provided. The heat pump system utilizes various heat sources in a general heating mode of the vehicle interior, and at the same time, maximizes the system performance by increasing flow of the refrigerant. The heat pump system may include: a compressor, a heating, ventilating, and air conditioning (HVAC) module; a heat-exchanger; a first expansion valve; a first connection line; a chiller; a second expansion valve; a second connection line; a third connection line; and a fourth connection line.