Today, an air conditioning system is considered standard in all modern vehicles. In the car, the air conditioner provides cooling in the summer and increases comfort while driving. In addition, the air conditioning system reduces humidity, thus protecting the windows from fogging in the fall. The car’s air conditioning system also includes the heater, which spreads pleasant warmth in the vehicle during the cold months. Learn now everything about the air conditioning, heating and climate control in the car.

Function of the air conditioning system in the car

The air conditioning system ensures that pleasant temperatures always prevail in the passenger compartment of the car. For this purpose, every car is equipped with a heating system that ensures pleasant temperatures in winter. Modern cars also have an air conditioning system that provides pleasant cooling of the interior when the outside temperature is high. A ventilation system is responsible for distributing the warm or cold air in the vehicle. One or more fans generate a stream of air that flows from the air vents into the passenger compartment of the car. The driver influences the air distribution via various controls, as well as the intensity or the desired temperature.

Car air conditioning and safety

Air conditioning in the car not only increases driving comfort, it also improves safety while driving. Among other things, the air conditioning system ensures that only dried ambient air is supplied to the interior. This prevents the windows from fogging up when the humidity is high in the fall, which improves the driver’s visibility. Intense heat in the summer quickly causes concentration to wane while driving. Some drivers also experience problems with their circulation when temperatures rise in the car. If, on the other hand, the temperature inside the car is comfortable, the driver can concentrate better. The air conditioning system thus helps to prevent accidents.

Function and components of the air conditioning system

The air conditioning system in a car is a closed system in which a refrigerant circulates under pressure. In principle, air conditioners in the car work the same way as any other air conditioner, the modes of operation hardly differ. In addition to the compressor as the most important part, the air conditioning system in the car consists of a condenser, air conditioning filter, expansion valve and evaporator. The refrigerant is compressed by a compressor and fed under pressure into the condenser. The condenser extracts heat from the refrigerant. The refrigerant is then passed through the air-conditioning dryer and expansion valve to the evaporator. The evaporator ensures that the air enters the passenger compartment at a significantly lower temperature.

Important components of the air conditioning system at a glance

1. Air conditioning compressor: The compressor, also known as the air conditioning pump, is the heart of the air conditioning system. In cars, these compressors are driven directly by the engine by means of belts and fixed by an air conditioning pump bracket or air conditioning pump fitting. The compressor compresses the refrigerant of the air conditioner under high pressure, and the temperature rises.
2. Condenser: From the compressor, the now gaseous refrigerant is fed into the condenser. This is usually located at the front of the vehicle near the radiator. A fan with impeller ensures that sufficient air flows through the condenser as required. This causes the condenser to release the heat contained in the refrigerant to the environment.
3. Air-conditioning dryer: Air-conditioning systems in cars have a dryer that works on the principle of the filter dryer. The air conditioner dryer filters suspended solids and contaminants such as abrasion from the compressor out of the refrigerant. The filter also removes moisture from the refrigerant, which can lead to corrosion or a fault in the system.
4. Expansion valve: The expansion valve controls the flow of refrigerant into the evaporator of the air conditioner. There is a steady pressure upstream of the expansion valve, while the refrigerant is allowed to relax into the evaporator downstream of the valve. Some air conditioners have a choke instead of the expansion valve through which the refrigerant is passed.
5. Evaporator: The evaporator is a heat exchanger that provides cooling to the interior. As the refrigerant downstream of the expansion valve expands into the evaporator, it changes from liquid to gas. Heat is extracted from the air flowing through the evaporator during this process. The large surface area ensures good cooling performance.

The heater and its components

The car’s heater provides comfortable temperatures inside when it is cold outside. In vehicles with internal combustion engines, the engine generates the heating energy for the heater. Cars with electric engines use an electric heater that is powered by electricity from the batteries. A heater is a legal requirement for cars in Germany and must be in working order. A short test before the main inspection is therefore recommended.

• Heat exchanger: The heat exchanger transfers the heat of the cooling water to the passenger compartment. The hot cooling water flows through it and an air blower passes through it.
• Heater blower: The heater blower is installed close to the passenger compartment and usually behind the dashboard. Here, the blower provides the necessary air flow in the vehicle.
• Heat exchanger hose: The heat exchanger is supplied with warm cooling water via the heat exchanger hose. The return to the engine is also via a hose.
• Heater housing: The heater housing accommodates the heater and, depending on the model, also houses the blower. Switches and control dampers may be integrated into the housing.
• Blower resistor: Many vehicle models have a resistor for the heater blower. This allows the blower to be switched in different stages.
• Heating element: A heating element for the electric auxiliary air heater generates heat from electricity. This means that the vehicle is heated even if the engine is not yet sufficiently warm.

Heating and air conditioning control

Temperature control of the interior requires perfect interaction between various components. A complex system ensures pleasant interior temperatures at all times of the year. The driver controls the desired temperature on the dashboard. Depending on the model, the system is operated via various switches, sliders or rotary knobs. To save energy, the air conditioning system should be switched off when cooling is not required.

• Heating switch
• Rotary control
• Air conditioning sensor
• Control unit of the air conditioner

Modern cars have an automatic control for air conditioning and heating. Here the driver can freely select the desired climate such as the temperature and sometimes also the humidity. The automatic air conditioning system controls the air conditioning accordingly or activates the heating function. For this purpose, an air conditioning sensor measures the climate in the interior and supplies the data to the control unit of the air conditioning system.

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