At idle (car not moving):
1. Less Engine Heat Dissipation: When a car is at idle, the engine is operating at a lower speed, which means less overall heat is being generated. As a result, the heat generated by the engine is not dissipated as quickly as when the car is moving. This heat can build up in the engine compartment, causing the air conditioner to be affected.
2. Reduced Airflow over Radiator and Condenser: At idle, the airflow through the car's radiator and condenser (components of the air conditioning system) is significantly reduced. The radiator works to cool down the engine coolant, while the condenser plays a crucial role in releasing heat from the refrigerant in the AC system. With reduced airflow, these components become less efficient in their respective tasks.
3. Limited Intake Air: When the car is at idle, there is less air flowing through the car's intake system, which can affect the efficiency of the AC compressor. Inadequate intake airflow can lead to reduced compression and, consequently, lower cooling capacity of the air conditioner.
When car is moving:
1. Improved Airflow: As the car starts moving, there is an increase in the airflow through the radiator, condenser, and intake system. This enhanced airflow helps dissipate heat more effectively from the engine and the AC system components.
2. Increased Compressor Speed: With increased engine speed while driving, the compressor in the air conditioning system is able to operate at a higher speed. This increased speed allows the system to generate more cooling power and provide colder air into the cabin.
3. Better Heat Dissipation: As the car moves, there is a greater flow of air over the exterior surface of the AC condenser. This facilitates efficient heat transfer from the refrigerant to the surrounding air, leading to improved cooling performance of the air conditioner.
In summary, the warm air at idle and cold air while driving can be attributed to the changes in airflow, heat generation, and operating speeds of various AC system components. As the car's speed increases, these factors combine to enhance the cooling performance of the air conditioner, resulting in colder air entering the cabin.
