How a Car AC Works : A Detailed Discussion

How a Car AC Works : A Detailed Discussion

For a long time, air conditioners were considered to be a pure luxury and were therefore only found in cars of the upper class. However, as the recognition of the fact that pleasant temperatures inside the car also serve as driving safety and, last but not least, the production costs fell, they are now part of the standard vehicle equipment or are available as an Option for all new vehicles. Therefore, it is necessary to know how a car ac works. Since the AC system in the car has enjoyed continued popularity in Germany since the 1980s, its absence or defect has had a significant impact on the vehicle. In this article, I will try to answer the question that how does air conditioning work in a car?

Air conditioners are usually reduced to their cooling function, but they can also heat in Winter and provide clean air through cabin air filters, which are also called Pollen or interior filters. So the driver and passengers are protected from Pollen, dust, soot, and gases.

Overview: How a Car AC Works?

Air conditioning is one of those elements that ensure your comfort once you board your vehicle. Driving comfort is an important consideration, which also explains why we need to change shock absorbers. It is somewhat essential for your well-being, so consider maintaining your air conditioning. The mode of operation of air conditioning in an automobile is similar to that of normal air conditioning. The procurement of automotive air conditioning is based on the principle of gas compression.

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The purpose of the principle of gas compression is to be able to relax the gas under pressure in order to obtain freshness. It wants the temperature to rise when the gas is compressed, and to fall when the gas relaxes. The cooling medium will then be obtained by relaxing the gas under pressure.

This is made possible by the intervention of a compressor powered by the accessory belt. The start-up of the compressor is dependent on the engine operating at high speeds. However, the compressor will raise the temperature of the gas, and cooling of the gas will provide only a lukewarm temperature. This is far from the expected result.


So, the best option is to cool down the gas before thinking about relaxing it. As a direct consequence of this cooling, you will get a more intense cold. To achieve this, the gas under pressure is passed through a cooling radiator, as is also the case with the engine water.

In short, AC is obtained by relaxing liquefied gas (always under high pressure). Once the desired result has been achieved, the passage of hot air from the outside to the cold storage site must be ensured. This step takes place in the evaporator, which becomes an active radiator, being colder than the ambient air.

It recovers moisture, and sometimes also dust, from the incoming air and ensures the removal of moisture in the form of water under the vehicle. That’s why you often see water coming out of your car.

how does air conditioning work in a car

Detail: How does Air Conditioning work in a car?

The most important thing in an AC is the refrigerant circuit, which, similar to a refrigerator, can absorb heat by changing its state of aggregation and returns elsewhere. The circuit begins by the air compressor sucking and compressing gaseous refrigerant. It is therefore also called a compressor. Due to the high pressure of 15-20 bar, the refrigerant Gas heats up and is now passed through the cooler (condenser). This is usually installed in the front of the vehicle and equipped with additional fans to cool off the refrigerant gas even when there is a traffic jam. Through this cooling, the refrigerant liquefies again but remains under high pressure.

It is then filtered through the dryer to remove moisture and foreign substances. We continue to the expansion valve. The liquid refrigerant passes through this tight hole to relax in the connector inside the evaporator and back into the gaseous state. For this process, heat is required, which is removed from the internal air flowing past the evaporator. The now colder air is directed back into the interior of the car. The evaporator acts as a heat exchanger and is normally installed in the blower box behind the instrument panel. By the way: Since cold air can hold less moisture than warm air, it comes to the exterior fins of the evaporator for Condensation of water, which is collected and routed to the outside. So in the summer, the water pools among parked cars explain. The compressor draws in the gaseous refrigerant again, and the cycle is closed.

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Thanks to numerous Measuring Probes, modern climate automation ensures that the System operates independently and is continuously regulated. For example, the pressure within the system must not be too high, and even the Icing of the evaporator is not desired.


Air Conditioning or Automatic Climate Control?

Air-conditioning systems are manual variants of vehicle air-conditioning, in which only the set stage is cooled. If it becomes too cold in the interior, it must be readjusted. Changing sunlight or tunnel driving can also make it necessary to adjust the cooling level. In the case of automatic climate control, the desired temperature is selected. Sensors then regulate the System, so that an automatic climate control automatically ensures that the desired temperature is reached and maintained. In general, automatic air-conditioning is, therefore, more efficient. Because the system does not provide more than the required power and unnecessary continuous operation is avoided. In this way, automatic climate control ultimately saves fuel compared to manual air conditioning.

Fuel Consumption of an Air Conditioner

Since the compressor requires energy for the compression of the refrigerant. Moreover, it is usually driven by a V-ribbed belt or now even by the drive shaft. It increases the working resistance of the engine, which is expressed in increased fuel consumption. If the System is not controlled by intelligent energy management, you can expect about 0.5-1.0 l more consumption per 100km. With valve-controlled compressors, it is about 0.2-0.5 l more consumption.

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Intelligent energy management, on the other hand, ensures that additional consumers who do not require maximum power are moved into “low-cost” energy Times. This means, for example, the motor brake: energy is a waste product here and can feed the additional consumer, while at the same time the brakes are protected. On the other hand, when the system is idle, it tries to prevent the energy consumption of additional consumers as far as possible, since the energy should only serve to maintain the internal combustion engine running and costs all additional fuel.

Optimize Consumption and Avoid Errors in Handling the Air Conditioner

It should be clear that by parking in the shade with foresight, the energy requirement of the air conditioning can be considerably reduced because the desired temperature is reached faster. If Shadow parking is not possible, sun visors and sun blinds help to reflect part of the solar radiation. If the interior has nevertheless become hot. You can first open the doors and windows of the car until a tolerable temperature is reached. All Windows and doors are closed and the air conditioning on recirculation.

Avoid leaving warm outdoor air in the vehicle. And seek an indoor temperature that is not more than 5°C below the outdoor temperature. The air flow should be cool and not cold or even frosty. In addition to saving energy, the recirculating air operation also reduces the addition of the pollen filter, which must, therefore, be cleaned or replaced less frequently. It also avoids selecting a low set temperature with only a weak blower, because the cooled air cannot reach the interior.

If you now come up with the idea, do not want to use the AC at all to save fuel, then be warned. Since the air-conditioning compressor is continuously driven by the Motor and is only operated without pressure, the bearings of the compressor shaft can get too little lubrication. You are leaking refrigerant from. The necessary sealing of the system is expensive. For the same reason, you should also use air conditioning from time to time in Winter. Finally, you should make sure that the ventilation is switched on regularly. This costs energy, but at the same time prevents the formation of a breeding ground for molds on the evaporator. If mushrooms spread out, there is a risk of Health for all occupants and the cleaning or replacement are time-and cost-intensive.


Various other Car Air Conditioner Problems

Car Air Conditioner Problems

What to do if the air conditioner stinks?

A stinky AC that secretes a rotten, fashionable smell is a sure indication of fungus infestation. Before you start fighting the mold, you should get to the bottom of the cause. Often, clogged drain valves or lines, the cause, to dissipate the condensation which forms on the evaporator, actually. The accumulated water creates a humid, warm climate and thus the perfect habitat for germs. Only a dry air conditioner is safe from mold infestation. It is therefore advisable to turn off the AC2-3 minutes before parking the car. And remove residual moisture inside the system via the blower.

After the cause of the mold has been identified and turned off, you can take part in the fight against germs. Car repair shops often offer a suitable disinfection service. However, as a layman, you can kill with appropriate means the specified germs. The disinfectant is usually spread out in the passenger compartment, all windows closed and the ventilation is set to recirculated air. Now you have to wait until the agent works, then ventilate the car well. If all germs inside the AC were killed, it will not stink after that. In a suitable Video for disinfection of the air conditioning, we demonstrate the procedure clearly.

Why Doesn’t the Air Conditioner Cool Down in a Car? Possible causes of a defect

Since that -how a car ac works- is now clear, we can also identify possible sources of error. Perhaps refrigerant has escaped through hard seals or loose connections in the coolant circuit? Owners of older vehicles, in particular, are aware of this Problem. Also checks whether the lines are damaged. By the way, air conditioning must only be refilled by suitably qualified personnel with new coolant. Not quite so simple is a broken compressor, which may have been fixed by not using the air conditioner.

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In such a case, only the exchange helps. But also the condenser, which cools down the pressurized Gas, may be damaged. The heat can no longer be sufficiently dissipated due to the impact of rocks on the Material. If the AC fails on particularly hot days or in a traffic jam, this can be due to the electric fan. Which is either defective or does not start due to a broken Sensor. Even in this case, replacing the defective components is the only remedy.

I will try to answer several queries about air conditioning work in a car. Moreover, I have tried to explain various problems of a car AC. If I have missed any point, please do share in the comment section.

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