Heat pump for a vehicle

A heat pump, comprising:

• a refrigerant loop comprising:
• a first heat exchanger;
• a first region of a second heat exchanger;
• a third heat exchanger;
• a fourth heat exchanger;
• a compressor having a low-pressure inlet, a mid-pressure inlet, and an outlet;
• a vapor generator positioned downstream of the outlet of the compressor and upstream of both the low-pressure inlet and the mid-pressure inlet, wherein the vapor generator comprises a first region and a second region that thermally interact with one another;
• an accumulator positioned immediately upstream of the compressor, wherein the accumulator comprises an inlet and an outlet;
• a first expansion valve positioned upstream of the accumulator, wherein the first expansion valve comprises an inlet and an outlet;
• a second expansion valve positioned upstream of the first region of the vapor generator;
• a third expansion valve positioned upstream of the third heat exchanger;
• a fourth expansion valve positioned upstream of the fourth heat exchanger;
• a first three-way valve positioned immediately downstream of the first expansion valve and immediately upstream of the accumulator, wherein the first three-way valve directs a first heat exchange fluid from the outlet of the first expansion valve to the inlet of the accumulator during at least one mode of operation;
• a first check valve positioned immediately downstream of the third heat exchanger;
• and
• a second check valve positioned immediately downstream of the fourth heat exchanger.