Wednesday, July 23, 2008

Get to know the evaporation and condensation systems as related with Air-Conditioning in cars.

JUST about every modern car, a truck or a saloon car of any type sold these days is having an air conditioning system in it. It's so common that most people take it for granted. You press the button for air conditioning while in your car and cold air starts to flow out of the car's vents. Air conditioning is a system used to create and maintain a comfortable driving environment inside a vehicle. It does this by transferring the heat from inside a vehicle to the outside keeping the temperature down inside the car. The system cools, dries and cleans the air. The most basic systems have manual temperature control but systems are becoming more and more complex with full climate control on a lot of modern cars which rely on a lot of sensors to maintain the selected temperature. It's easy as well as simple, and it's a major convenience. Could you imagine driving to a job interview or for an appointment with a vulnerable person in the city center if your car didn't have air conditioning systems? By the time you got to your interview, you'd be a sweaty, stinky mess. Have you ever wondered how the air conditioning in vehicles works? If you're like most people, you probably haven't. But here is a little education you can take a note. Air conditioning is the process by which air is cooled and dehumidified. The air conditioning in cars, as well as those in offices all work the same way. Even a refrigerator in effect, works like an air conditioner. While there are many physical principles that relate to air conditioning, that explains the general concepts of automotive air conditioning, the components used is what one need to know to keep car's air-conditioning system working properly.

This is how an Air-Conditioning system in cars looks like in its position inside a saloon car.

Did you know that when you turn on the air-condition in your car, you are burning extra gasoline to make yourself feel cooler? It's weird to think that by burning something you become cooler, but it's true. According to an elementary physics study, air conditioning systems operate on the principles of evaporation and condensation. Here's a simple example of evaporation. Imagine that you're swimming around in your neighbor's backyard pool on a summer day. As soon as you get out, you start to feel cooler. Why? The water on your body starts to evaporate and turns into water vapor. And as it evaporates, it draws heat away from your body, and you get goose bumps. Now let's say your neighbor hands you a big glass of ice-cold lemonade. You take a sip and set it down on a table. After a minute or two, you notice that water has collected on the outside of the glass. This is condensation. The air surrounding the glass becomes cooler when it encounters the cold glass, and the water vapor the air is carrying condenses into water. Both of these examples occur at normal atmospheric pressure. But higher pressures can also change a vapor (or a gas) into a liquid. For example, if you look at a typical butane cigarette lighter, you can see liquid inside it. But as soon as you push down on the button, butane gas comes out. Why? The butane is under high pressure inside the cigarette lighter. This high pressure causes the butane to take liquid form. As soon as the butane is released and it encounters normal atmospheric pressure, it turns back into a gas. Those are the basic ideas and how do they apply to making car's vents blow cool air? The principles of evaporation and condensation are utilized in car's air-conditioning system by a series of components that are connected by tubing and hoses. There are six basic components namely the compressor, condenser, receiver-drier, thermostatic expansion valve, the evaporator and the life-blood of the air-conditioning system, the refrigerant.

And this is the machine inside a compact that shows vents through which fresh and cold air comes out when it’s switched on.

Refrigerant is a liquid capable of vaporizing at a low temperature. In the past, R-12 refrigerant was used in cars. But this chlorofluorocarbon (CFC) is harmful to the earth's ozone layer. Consequently, all vehicles built after 1996 use R-134A, a more environmentally friendly refrigerant. The best thing about air conditioning is that all you have to do is press a button to make it work. Air conditioning systems are pretty reliable. On a modern and relatively new vehicle, it is rare to have problems. And if there are problems, they are pretty much one of two things such like, there is no cool air or insufficient cool air. This is if you own an older car and its air-conditioning system doesn't seem to be working properly.

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