You’re no doubt grateful for the rush of cool air that provides relief from the severe summer heat when you turn on your vehicle’s air conditioning, but have you ever wondered how it actually works?
Just as with anything else that powers your vehicle, the underworkings of your car air conditioning system are pretty complex. Here are the basics.
There are five pieces and parts that make up your car’s AC system:
- Expansion valve/orifice tube
Here’s how all these parts work together to provide air flow and refreshment from heat and humidity.
The compressor is a pump that is attached to your engine’s crankshaft by a belt. This compressor starts the process by pulling in refrigerant in a low-temperature, low-pressure gaseous state. As this gas enters the compressor, it gets pressurized and converted into high-temperature, high-pressure gas.
Next, this pressurized gas goes to the condenser, which is responsible for radiating heat out of the system. The heated gas gets cooled and forms a liquid, just like steam cooling and condensing back into water.
The refrigerant then flows to the receiver-dryer, which contains filters to remove debris (like dust and dirt) and desiccants to remove moisture.
From there, the refrigerant enters through the expansion valve (or an orifice tube in some vehicles). These parts allow the refrigerant to expand, which reduces the pressure.
Lastly, the refrigerant enters the evaporator between 32 and 38 degrees Fahrenheit. The evaporator is in the cabin, rather than under the hood. Its role is to absorb heat, and it does this by boiling the liquid refrigerant and converting it back into steam, so it can absorb the heat from the air inside the cabin. The evaporator also takes any humidity out of the air, increasing the cooling effect.
How to Maximize the Cooling Effectiveness of Your Air Conditioner
Now that we know where the cold air comes from, how can we ensure that we’re operating our vehicles to maximize that fresh, cool feeling?
STAY ON TOP OF MAINTENANCE
Your cabin air filter can get dirty quickly, which prevents optimal airflow. Check your cabin air filter regularly to make sure it’s clean.
DON’T PRECOOL YOUR AC
It seems counterintuitive, but when your car is idling, the AC can’t work very effectively. The compressor relies on the engine running faster (which it can only do under driving conditions) in order to do its job well.
OPEN YOUR WINDOWS
Why would you do this when it’s so hot outside? Because the air inside the car is much hotter than the outside air. Pulling in fresh air from the outside for just 20 seconds or so (not your entire drive) will get things moving in a cooler direction faster.
CRANK IT TO THE LOWEST TEMPERATURE
Believe it or not, if you set your temperature higher, the AC actually has to work harder because it’s forcing the system to reheat cooled air.
TURN OFF YOUR AUTO STOP/START
If you have a vehicle that automatically shuts off when the car is idling, this actually forces the AC to work much harder because the compressor can’t run when the engine is off.
TURN OFF THE RECIRC
When you have the AC in recirculation mode, it pulls air from the front of the cabin back through the system. This keeps the driver and front passenger cool, but those in the rear passenger seats won’t get the same cool airflow.
TURN OFF YOUR AIR IF CLIMBING
Especially if you have an older vehicle, climbing steep hills for extended distances (for example, driving up to Flagstaff from Phoenix) is very taxing on your engine and your AC. This can also lead your engine to overheat, which can be a dangerous and costly situation.
USE YOUR AUTOMATIC CLIMATE CONTROL
In many newer vehicles, automatic climate control is the most efficient way to maintain a cool environment inside the cabin.
The instructors at Stop and Go Driving School are ready with all sorts of driving tips to help you make the most of your vehicle’s systems and stay safe on the road. Learn more about what we offer.