Heat pump system for vehicle

A heat pump system for a vehicle which comprises:

• a compressor mounted on a refrigerant circulation line (R) for compressing and discharging refrigerant;
• an internal heat exchanger mounted inside an air-conditioning case for exchanging heat between air inside the air-conditioning case and the refrigerant discharged from the compressor;
• an evaporator mounted inside the air-conditioning case for exchanging heat between the air inside the air-conditioning case and the refrigerant supplied to the compressor;
• an external heat exchanger mounted outside the air-conditioning case for exchanging heat between the refrigerant circulating through the refrigerant circulation line (R) and outdoor air;
• a second expansion valve mounted on the refrigerant circulation line located at an outlet of the internal heat exchanger to selectively expand the refrigerant discharged from the internal heat exchanger;
• a first expansion valve mounted on the refrigerant circulation line located at an inlet of the evaporator to expand the refrigerant supplied to the evaporator, further comprising:
• a coolant circulation line (W) configured to circulate coolant toward electronic units of the vehicle to cool the electronic units;
• and
• a refrigerant-coolant heat exchanger configured to exchange heat between the refrigerant circulating through the refrigerant circulation line (R) and the coolant circulating through the coolant circulation line (W),
• wherein the refrigerant circulating through the refrigerant circulation line (R) radiates heat to the coolant and the outdoor air through the refrigerant-coolant heat exchanger and the external heat exchanger in an air-conditioning mode, and
• wherein the refrigerant circulating through the refrigerant circulation line (R) absorbs heat from the coolant and the outdoor air through the external heat exchanger and the refrigerant-coolant heat exchanger in a heat pump mode
• wherein the refrigerant circulation line (R) is configured in such a way that the refrigerant circulates in order of the compressor, the internal heat exchanger, the refrigerant-coolant heat exchanger, the external heat exchanger, the first expansion valve, the evaporator and the compressor in the air-conditioning mode, and
• wherein the refrigerant circulation line (R) is configured in such a way that the refrigerant circulates in order of the compressor, the internal heat exchanger, the second expansion valve, the external heat exchanger, the refrigerant-coolant heat exchanger and the compressor in the heat pump mode;
• wherein the refrigerant circulation line (R) comprises two lines diverging in the refrigerant circulation line (R) located at the outlet of the internal heat exchanger:
• a first refrigerant circulation line (R1) which is configured in such a way that the refrigerant discharged from the internal heat exchanger circulates in order of the refrigerant-coolant heat exchanger, the external heat exchanger, the first expansion valve, the evaporator and the compressor in the air-conditioning mode;
• and
• a second refrigerant circulation line (R2) which is configured in such a way that the refrigerant discharged from the internal heat exchanger circulates in order of the second expansion valve, the external heat exchanger, the refrigerant-coolant heat exchanger and the compressor in the heat pump mode.