Which substance cools the air in an automobile air conditioner?

The substance that cools the air in an automobile air conditioner is refrigerant. In air conditioning systems, refrigerants are chemicals specifically designed to change states between gas and liquid at relatively low temperatures, allowing them to absorb heat from the cabin air effectively.

When the refrigerant enters the evaporator inside the car's cabin, it expands and evaporates, absorbing heat from the air that is blown over the evaporator coils. As the refrigerant absorbs this heat, it cools the air before it is circulated back into the passenger compartment. The cycle continues as the refrigerant is then compressed back into a liquid form and cycled through the system again. This is a critical process in vehicle climate control systems, ensuring that passengers remain comfortable regardless of external temperatures.

While substances like antifreeze and coolant are important in the engine cooling system, they serve a different purpose and are not used to cool the air in the cabin. Oil is used to lubricate engine components and is not involved in the air conditioning process, further differentiating it from the role of refrigerant.