Heat pump including at least two refrigerant injection flow paths into a scroll compressor

1. A heat pump including at least two refrigerant injection flow paths into a scroll compressor, the heat pump comprising:

a main circuit which comprises the scroll compressor, a condenser for condensing refrigerant passed through the scroll compressor, an expansion valve for expanding the refrigerant passed through the condenser, a phase separator for separating the refrigerant into liquid refrigerant and vapor refrigerant, and an evaporator for evaporating refrigerant, wherein the scroll compressor is provided with a first refrigerant injection port between an inlet of the scroll compressor and an outlet of the scroll compressor, and a second refrigerant injection port between the inlet and the first refrigerant injection port;

a first refrigerant injection flow path, which is bypassed from the phase separator and is connected to the first refrigerant injection port of the scroll compressor;

an internal heat exchanger installed between the phase separator and the evaporator;

a second refrigerant injection flow path, which is bypassed between the phase separator and the internal heat exchanger, and is connected to the second refrigerant injection port of the scroll compressor wherein the second refrigerant injection flow path is passed through the internal heat exchanger.

2. The heat pump of claim 1 , wherein the expansion valve comprises a first expansion valve which is disposed between the condenser and the phase separator, and a second expansion valve which is disposed between the internal heat exchanger and the evaporator.

3. The heat pump of claim 1 , wherein a refrigerant control valve is installed at the second refrigerant injection flow path to throttle the refrigerant before flowing into the internal heat exchanger.

4. The heat pump of claim 3 , wherein the internal heat exchanger comprises a first refrigerant pipe and a second refrigerant pipe which is formed to surround the first refrigerant pipe, and one of the refrigerant flowing into the evaporator and the refrigerant injecting into the scroll compressor passes through the first refrigerant pipe and the other refrigerant of those passes through the second refrigerant pipe.

5. The heat pump of claim 1 , wherein the expansion valve comprises a first expansion valve installed between the condenser and the phase separator, and a second expansion valve installed between the internal heat exchanger and the evaporator, wherein, a first refrigerant control valve, is installed at the first refrigerant injection flow path and a second refrigerant control valve is installed at the second refrigerant injection flow path, and further comprising a controller which controls opening degrees of the first refrigerant control valve and the second refrigerant control valve.

6. The heat pump of claim 5 , wherein the controller controls that the first refrigerant control valve and the second refrigerant control valve are opened at a same time according to a heating load of the heat pump.

7. The heat pump of claim 5 , wherein the controller controls that the opening degree of the second expansion valve is larger than or equal to the opening degree of the first expansion valve.

8. The heat pump of claim 5 , wherein when the heat pump is started, the controller controls that the first and second expansion valves are started to open and the first and second refrigerant control valves are closed,

and then, if the refrigerant injection is demanded after first and second expansion valves are opened, the controller controls that at least one of the first refrigerant control valve and the second refrigerant control valve is opened.

9. The heat pump of claim 8 , wherein the controller controls that the first refrigerant control valve and the second refrigerant control valve are opened in sequence according to a heating load of the heat pump.

10. The heat pump of claim 1 , further comprising a water heater and a heater which are connected to the condenser by a hot water circulation flow path, wherein the water heater comprises a hot water tank for containing hot water, and the heater comprises an air heater for heating an air in a room, wherein a control valve is installed at the hot water circulation flow path to introduce the hot water heated in the condenser into at least one of the water heater and the heater.