What does gas-compression cooling involve, concerning refrigerant gas?

Gas-compression cooling, commonly used in air conditioning and refrigeration systems, involves both compression and expansion of refrigerant gas as key processes in the cooling cycle. In this system, the refrigerant gas is first compressed by the compressor, which raises its temperature and pressure. This high-pressure gas then travels to the condenser, where it releases heat and changes phase to become a liquid.

Following this, the liquid refrigerant is allowed to expand through an expansion valve or similar device, which reduces its pressure and temperature. This low-pressure refrigerant then enters the evaporator coil, where it absorbs heat from the indoor air, thereby cooling the space.

The sequential processes of compression and expansion are essential for creating the cooling effect, making the option mentioning both processes the correct one. Understanding this cycle is fundamental for anyone studying the principles of HVAC systems and how they operate to provide effective cooling.