Can the Air Conditioning Be Turned On Without Starting the Engine?
3 Answers
No, the air conditioning cannot be turned on without starting the engine, because the air conditioning compressor cannot operate without the engine running, and thus the air conditioning cannot provide cooling. The car air conditioning cooling system consists of components such as the compressor, condenser, receiver-drier, expansion valve, evaporator, and blower. These parts are connected by copper pipes and high-pressure rubber hoses to form a sealed system. When the cooling system is in operation, the refrigerant circulates through this sealed system in different states. The process is mainly divided into four stages: compression, heat dissipation, throttling, and heat absorption. The compressor draws in low-temperature, low-pressure refrigerant gas from the evaporator outlet, compresses it into high-temperature, high-pressure gas, and discharges it from the compressor. The high-temperature, high-pressure superheated refrigerant gas then enters the condenser, where, due to the reduction in pressure and temperature, it condenses into a liquid and releases a significant amount of heat. The high-temperature, high-pressure refrigerant liquid passes through the expansion device, where its volume increases, and its pressure and temperature drop sharply, exiting the expansion device in a mist-like form. The mist-like refrigerant liquid enters the evaporator, where, because the boiling point of the refrigerant is much lower than the temperature inside the evaporator, it evaporates into a gas. During this evaporation process, it absorbs a large amount of heat from the surroundings, and the resulting low-temperature, low-pressure refrigerant vapor re-enters the compressor. When using the car air conditioning, attention should be paid to the timing of turning the air conditioning on/off, the use of the internal/external air circulation, and the direction of the airflow. It is best to adjust the airflow direction to blow only toward the face, with the air vents positioned horizontally or slightly upward for optimal performance.
I've been driving for twenty years, and this issue really depends on the situation. With traditional fuel-powered vehicles, you definitely can't use the air conditioning for cooling without starting the engine, because the compressor is driven by the engine belt. However, the blower fan can still work, consuming only the battery's power, but it will just blow natural air. In winter, you might get some residual heat right after turning off the engine, but it cools down after a while. You have to be careful with the battery power—once, a friend of mine listened to music and ran the blower fan for over an hour with the engine off, and the battery drained so much that the car wouldn't start, forcing him to call for roadside assistance. New energy vehicles are different, though. The compressor runs directly on electricity, so you can get cold or warm air without starting the engine. It's quiet and convenient, especially useful when waiting, but it does consume battery power and affect the driving range.
As a new energy vehicle owner, I often use the air conditioning without starting the engine. The car's AC is powered by the high-voltage battery, which has nothing to do with the engine, so the cooling and heating functions are available anytime, making it super convenient. When parked waiting for someone or charging, turning it on instantly cools the cabin comfortably without the engine noise of traditional cars. However, you need to watch the battery level—using AC consumes a lot of power. Once, I took a two-hour nap in the car with the AC on, and the range dropped by 30 kilometers. It's fine for short periods, but for extended use, it's best to plug in the charging cable to avoid draining the traction battery. Traditional fuel car owners shouldn't even try this—their compressors don't work when the engine is off, and they can only blow natural air, which risks draining the 12V battery.
