Final answer:
In the heat mode, the suction line entering the compressor contains low-pressure refrigerant vapor that has absorbed heat from the outdoor air. This vapor is compressed by the electrically driven compressor, increasing its temperature and pressure, before it condenses in the condenser coils inside the space being heated.
Step-by-step explanation:
In heat mode, the suction line entering the compressor contains low-pressure refrigerant vapor, which has absorbed heat from the outside air at the evaporator. As you've outlined, the electrically driven compressor then compresses this vapor, raising its temperature and pressure. The high-temperature gas then enters the condenser coils inside the heated space, where it releases heat to the environment as it condenses into a liquid. Following that, the high-pressure liquid flows through a pressure-reducing valve, cooling as it expands before returning to the outdoor evaporator coils to absorb more heat from the outdoor air and continue the cycle. This process ensures that energy is efficiently transferred from the outside to the inside of the room in a heating scenario.