Heat pump system for vehicle

1. A heat pump system for a vehicle, the heat pump system comprising:

an air conditioner apparatus connected to a first refrigerant line through which a first refrigerant is circulated, and including a first condenser, a first expansion valve, a first evaporator, and a first compressor;

a sub-centralized energy (CE) module including a second compressor configured to compress a second refrigerant and a second evaporator connected to the first refrigerant line of the air conditioner apparatus, to adjust a temperature of the first refrigerant by selectively exchanging thermal energy which is generated during condensation and evaporation of the second refrigerant circulating along a second refrigerant line with the first refrigerant; and

a gas injection unit provided in the air conditioner apparatus to increases a flow rate of the first refrigerant circulating in the first refrigerant line by bypassing a part of the first refrigerant to the first compressor in a heating mode or a low-temperature dehumidification mode of the vehicle,

wherein the first evaporator is positioned in series with the second evaporator in the first refrigerant line, and

wherein the second compressor is integrally formed with the first compressor.

2. The heat pump system of claim 1 , wherein the sub-CE module further includes:

a second condenser connected to the second compressor through the second refrigerant line, and configured to condense the compressed second refrigerant supplied from the second compressor by heat-exchange with the first refrigerant;

a second expansion valve connected to the second condenser through the second refrigerant line and configured to expand the second refrigerant; and

the second evaporator connected to the second expansion valve through the second refrigerant line, and configured to evaporate the second refrigerant supplied from the second expansion valve through heat-exchange with the first refrigerant introduced through the first refrigerant line to supply the evaporated second refrigerant to the second compressor.

3. The heat pump system of claim 2 , wherein the first condenser is detachably coupled to the second condenser and is provided in the first refrigerant line.

4. The heat pump system of claim 2 , wherein the second evaporator is detachably coupled to the first evaporator and provided in the first refrigerant line.

5. The heat pump system of claim 2 , wherein the first expansion valve is provided between the first evaporator and the second evaporator, and is detachably coupled to the first evaporator and the second evaporator.

6. The heat pump system of claim 2 , wherein the first expansion valve and the second expansion valve are each an electronic expansion valve that selectively expands a refrigerant while controlling a flow of the refrigerant.

7. The heat pump system of claim 2 , wherein the gas injection unit includes:

a flash tank provided in the first refrigerant line between the second condenser and the first expansion valve, and configured to separate the first refrigerant that has passed through the first and second condensers into a gaseous refrigerant and a liquid refrigerant and selectively discharge the gaseous refrigerant and the liquid refrigerant;

a bypass line connecting the flash tank and the first compressor and configured to selectively supply the gaseous refrigerant of the first refrigerant from the flash tank to the first compressor;

a valve provided in the bypass line; and

a third expansion valve provided between the first condenser and the second condenser, and configured to selectively expand the first refrigerant.

8. The heat pump system of claim 7 , wherein the third expansion valve expands the first refrigerant passing through the first condenser in the heating mode or the low-temperature dehumidification mode of the vehicle.

9. The heat pump system of claim 7 , wherein the third expansion valve is detachably coupled to the first condenser and the second condenser.

10. The heat pump system of claim 2 , wherein the gas injection unit includes:

a plate heat exchanger provided in the first refrigerant line between the first condenser and the first expansion valve;

a bypass line including a first end portion connected to the first refrigerant line between the first condenser and the plate heat exchanger and a second end portion connected to the first compressor through the second condenser and the plate heat exchanger; and

a third expansion valve provided in the bypass line at a front end portion of the second condenser.

11. The heat pump system of claim 10 ,

wherein the second condenser is provided in the bypass line between the first condenser and the plate heat exchanger, and

wherein the third expansion valve expands the first refrigerant flowing into the bypass line through the first condenser in the heating mode or the low-temperature dehumidification mode of the vehicle.

12. The heat pump system of claim 2 , wherein the second compressor has a capacity smaller than a capacity of the first compressor.

13. The heat pump system of claim 1 , wherein the gas injection unit operates with the sub-CE module in the heating mode or the low-temperature dehumidification mode of the vehicle.

14. The heat pump system of claim 1 , wherein the first condenser is connected to a radiator and a heater through a coolant line, and is configured to condense the first refrigerant by heat-exchange with a coolant introduced therein with the first refrigerant.

15. The heat pump system of claim 14 , wherein the first condenser is configured to supply the coolant having a temperature which is increased while condensing the first refrigerant in the heating mode, the low-temperature dehumidification mode, and a high-temperature dehumidification mode of the vehicle to the heater through the coolant line.

16. The heat pump system of claim 1 , wherein the first evaporator is connected to an electrical component and a battery module through a coolant line, and is configured to absorb waste heat of the electrical component while heat-exchanging a coolant introduced therein with the first refrigerant, or to supply the coolant heat-exchanged with the first refrigerant to the battery module.

17. The heat pump system of claim 1 , wherein the air conditioner apparatus further includes an accumulator provided in the first refrigerant line between the first evaporator and the first compressor.

18. The heat pump system of claim 1 , wherein the first refrigerant and the second refrigerant are different from each other.

19. The heat pump system of claim 1 , wherein the first expansion valve expands the first refrigerant introduced into the first refrigerant line and introduces the first refrigerant into the first evaporator when cooling a battery module by use of a coolant which undergoes heat transfer with the first refrigerant.