Do You Need to Turn on AC When Using External Air Circulation?

[VanMalia]

It is possible to not turn on the AC. External air circulation and AC are two completely different mechanisms with no connection or relationship between them. Vehicle external air circulation uses a fan to draw outside air into the cabin, allowing passengers to breathe fresh air from outside. The air ducts between the outside and inside of the vehicle are open during external circulation. The air in the car's fan comes from outside, and even if the fan is not turned on, airflow is still drawn into the cabin while driving, replenishing the fresh air inside. AC (Air Conditioner) is the switch that controls the air conditioning. To cool the car, the AC switch must be turned on. Pressing the AC button engages the compressor clutch, causing the engine to drive the compressor. The compressor then continuously compresses the refrigerant and delivers it to the evaporator. The refrigerant expands and absorbs heat in the evaporator, cooling it. The evaporator then cools the air blown by the fan, allowing cold air to be blown out from the air vents. The refrigerant used in car air conditioning is typically R134a, which needs to be replaced periodically. If the refrigerant is not replaced for a long time, it can affect the cooling efficiency and speed of the air conditioning system. Strictly speaking, the AC button controls the compressor. The AC switch controls the electromagnetic clutch, and for the car's compressor to operate, the electromagnetic clutch must be engaged while power is supplied. Only when the compressor is turned on will the car start blowing cold air. In other words, external air circulation is used independently and is not related to the air conditioning system. In summer, pressing the AC button turns on the air conditioning to cool the cabin. Turning on external air circulation without AC only allows fresh outside air to enter the cabin but does not lower the temperature inside. Car air conditioning has both internal and external circulation functions. External circulation is mainly used to ensure fresh air inside the cabin, suitable when the air inside is stale, such as when smoking in the car. It is also useful during high-speed driving when opening windows for ventilation is inconvenient. When driving through dusty construction sites or in heavy traffic, it is better to use internal circulation. Turning on external circulation in heavy traffic may allow exhaust fumes to enter the cabin. When using the heating function, there is no need to press the AC button, as car air conditioning heating is unrelated to the compressor, refrigerant, or evaporator.