Air conditioning is a technology designed to control the thermal environment of an indoor space by managing temperature, humidity, and air filtration. The underlying principle relies on the phase change of refrigerants; a circulating refrigerant absorbs heat energy from the indoor air as it evaporates in the evaporator coil, thereby cooling the air. This heat-laden refrigerant then travels to the condenser, where it rejects the absorbed heat to the external environment, causing it to condense back into a liquid state. Modern systems are designed to maximize energy efficiency while maintaining occupant comfort and improving indoor air quality through the removal of airborne contaminants.