Car air conditioning is a process in which the air flowing in your car is cooled for passenger comfort through a refrigeration cycle.
The most basic form of vehicle air conditioning attaches an evaporator to the car's heating and ventilation system. Next, an electrical pump circulates refrigerant throughout the cooling unit, where it absorbs heat from the interior of the vehicle before releasing it outside.
Refrigerants that make up the car air conditioner units are typically made up of four parts hydrogen, two parts carbon, one part oxygen, and varying numbers of parts fluorine.
Ideally, there are two parts to the car air conditioning system. The high-pressure side occurs when the compressor pushes the high-pressure gas into the condenser, through the vapour tubes into the evaporator, via the orifice tube.A car air conditioning works through two back to back cycles; the low pressure side and the high-pressure side. The low pressure side occurs as the high-pressure liquid turns to cold vapour at the thermal expansion valve junction. The low pressure after the thermal expansion valve makes the gas expand. As the pressurised gas turns into a low-pressure gaseous form, it becomes cold before returning to the compressor.
A compressor increases the pressure on the hot gases to condense into a liquid, gaseous state. Some modern cars have an expansion valve that senses pressure and lets some excess warm air escape as cool air enters the vehicle to prevent uncomfortable temperatures during extremely warm days or while sitting in traffic. Then, the refrigerant flows back into the compressor.
The refrigerant enters via a coil into the condenser, which is located in front of the car's radiator. Here, the low pressure liquid refrigerant gives up its heat to the surrounding air and turns back into a gas form. Next, the high pressure refrigerant in liquid form enters a little reservoir called the receiver dryer. Finally, the desiccant materials remove moisture from the refrigerant to prevent the formation of ice crystals that can cause blockage of the air conditioning system.
After the receiver dryer, the refrigerant enters the evaporator coil.
The evaporator units absorb heat from the car interior, through the low-pressure tubes, and back to the compressor, where the whole process begins again.
The temperature of the air blown into the car can be controlled by varying the speed of the fan blades in the evaporator and condenser. The faster these blades spin, the colder the air will be that's circulated into your car. Many newer cars also have climate control panels that allow you to set a specific temperature for the interior cabin. An expert can easily help you if you have any issues.Most car air conditioning units operate in a similar manner. This is the basic principle of how car AC works: One end of the system attaches to your car's heating and ventilation ducts, while the refrigerant lines run from these components through a compressor in your engine compartment. The compressor increases the pressure in the refrigerant lines and forces it into a high-pressure liquid as it passes through a condenser placed in front of your radiator. An electronic or electric pump then sends this cool liquid throughout your interior climate control unit, where it flows past fan blades that draw heat from inside your vehicle and release it outside before converting back to a gas and repeating the cycle during cooling mode. In some car models, an expansion valve is used to regulate the flow of warm air into the interior. Temperature is regulated by controlling the speed of the fan blowing over the evaporator and condenser, as well as your car's climate control unit that sets a specific temperature for the interior cabin. Your AC unit will also have a filter that should be periodically cleaned to ensure proper airflow and cooling.
The recycle function is used to circulate the air inside your car's passenger side. This helps to maintain a comfortable temperature and prevents the build-up of pollutants. When the system is in recycle mode, it will close off the fresh air intake and re-circulate the air already inside the car. This helps keep the temperature consistent and eliminates any bad smells from outside.
The climate control system in your car is the main component that regulates how much heat or cold air enters your vehicle's passenger compartment. It has a separate mode for both heating and cooling, along with an automatic setting to activate either when needed. Your unit will also have a button to activate the recycle function, which circulates and recirculates the air inside your passenger cabin. The climate control system typically includes:
The air intake is where fresh air enters the car's climate control unit, sometimes through an air conditioner filter designed to trap dust and pollen. This is where one end of the refrigerant line attaches to your HVAC system.
Fan blades draw heat from inside your vehicle and release it outside before the air is converted back to a gas and repeats the cycle. To help achieve the cooling effect, the evaporator is typically placed in the dashboard or under the seats.
The compressor increases the pressure in the refrigerant line and forces it into a liquid state as it passes through a condenser placed in front of your radiator.
This is located in front of your car's radiator, the condenser gives up its heat to the surrounding air and turns it back into a gas. It then returns to the compressor, where the cycle begins again.
This panel allows you to set a specific temperature for the interior cabin. It also includes buttons to activate fan speed, AC, heating, and recycle functions. In many cases, the climate control unit is integrated with the car's infotainment system.
This screen provides information about the current settings for your climate control and AC unit. It may also show diagnostic codes to help you troubleshoot any problems with your system.
A car's AC system does not directly use fuel. However, running your air conditioner will increase the strain on your engine and cause it to use more petrol than usual. Why? Because car air conditioning systems are pump driven by a serpentine belt attached to the engine's crankshaft. This is why your AC will automatically turn off after several minutes when you are idling in traffic or at a stoplight. The only time this is not true is if your vehicle has an AC compressor clutch, which switches between using the belt-driven AC compressor and an electric one that doesn't require any power from the engine.
There are some main components to keep an eye on to help maintain your automotive air conditioning systems.
Check the air conditioner filter regularly and clean or replace it as needed. This will help to ensure proper airflow and cooling.
Keep the evaporator and condenser clean and clear of debris. This will help optimise performance, prevent overheating, and keep the system running smoothly.
Have the refrigerant level checked periodically and topped up if necessary. Low refrigerant levels can cause your AC unit to work less efficiently.
See a mechanic if you notice any problems with your AC system, such as leaks, strange noises, or poor performance. These issues can be repaired without having to replace the entire system. However, if the car air conditioning system fails completely, it may require replacement.