HEAT PUMP SYSTEM FOR A VEHICLE

A heat pump system for a vehicle is provided to improve the overall cooling and heating performance and efficiency by increasing the enthalpy difference of the evaporator or chiller to be significantly large at the time of cooling or heating vehicle interior. The heat pump system further improves the overall cooling and heating performance by heating the vehicle interior by using a high-temperature coolant, and by removing the conventional heat-exchanger applied for subcooling of the refrigerant. The heat pump system is further configured to exchange heat between refrigerants having different temperatures, and is additionally configured to employ a heat-exchanger configured to exchange heat between the coolant and the refrigerant.