Final answer:
In the cooling mode, after leaving the compressor, the hot gas first flows to the condenser coils, where it releases heat to the indoor space and condenses into a liquid, then it moves through a pressure-reducing valve before returning to the outdoor evaporator coils.
Step-by-step explanation:
When operating in the cooling mode, hot gas leaves the compressor and first flows to the condenser coils. The electrically driven compressor increases the temperature and pressure of the refrigerant gas and pushes it into the condenser coils. These coils are located inside the heated space, such as the inside of a building for an air-conditioning unit. Here, due to the higher temperature of the refrigerant gas compared to the room temperature, heat transfer takes place. This causes the refrigerant gas to release heat to the room and condense into a liquid. After condensation, the liquid refrigerant is then directed through a pressure-reducing valve, commonly known as an expansion valve. Once it passes through this valve, it cools down due to expansion and then returns to the outdoor evaporator coils to pick up heat and restart the cycle.