Until recently, air conditioning was regarded being an expensive optional extra, only fitted to ab muscles top of the range cars and deemed as not really essential for our temperate climate. Nowadays however, it is fitted to any or all but the absolute most basic of models and its benefits are enjoyed by most of us, the absolute most obvious being that it gives us nice, cooling air on hot summer days.
This isn't its most useful attribute however. It gets the added convenience of drying the air within the cabin and this reduces the tendency for the windows to steam through to wet days along with keeping you more awake and alert on longer journeys.
So, so how exactly does it work? Well, without going too deep in to the physics of finished, it uses the principle that to change their state of a substance from a fluid to a fuel and then back to a fluid again, the substance takes away and gives out energy in the proper execution of heat.
For a substance, and we'll use water for example, to change from a fluid to a fuel, it requires plenty of heat energy to make that transformation.
Whenever you get out of the shower, even on a warm day you're feeling cold. That is as the water on the body takes heat energy from the skin to change it into a fuel and evaporate. The Airco system does the same, and I'll try and explain the function of the system very briefly.
A compressor does exactly as its name suggests and compresses the refrigerant gas. Compressing the gas causes it to go up in temperature and also gets the aftereffect of raising the boiling point. It flows to a condenser where the hot, compressed gas condenses into a warm liquid, giving off heat because it changes its state.
The condenser is the bit at the front end of the car that appears like another radiator. After that it flows via a restrictor, and on one other side of the restrictor the pressure reduces dramatically.
After that it flows to an evaporator where the reduced pressure liquid then evaporates right into a gas. Since it changes state back into a fuel, it draws heat from its surroundings. The air coming in to your car's heater system passes on the evaporator and because it does so it's the warmth taken from it by the cold evaporator, so you get nice cold air in to the cabin.
Now, as the evaporator is cold and the air flowing over it is substantially warmer, water condenses on the surface. This really is similar to once you get a nice, cold beer from the fridge, the bottle instantly becomes wet and you've to wear it a coaster to avoid it leaving a mark on your polished table. This really is where the system dries the air in the cabin, drawing out the moisture from the incoming air passing on the evaporator as I described earlier, and also why you can see water dripping out of under your vehicle when you have parked up.
So that is air conditioning in summary, however it doesn't end there. In order to keep your air conditioning functioning efficiently, there's a quantity of routine maintenance required.
In the refrigerant circuit there's a small amount of a unique oil that is carried around the system by the refrigerant gas. This really is Polyalkylene Glycol oil, more commonly called PAG oil, and along with lubricating the moving elements of the compressor, it keeps all of the seals between the pipe-work and components moist. The molecules of the refrigerant gas are really small, and if the air conditioning is powered down for almost any period of time, the oil drains back to the lowest point, the seals dry to a certain degree and contract, and a small amount of refrigerant gas could be lost. This reduces the efficiency and therefore the cooling capacity of the system and a re-gas is necessary.
All automotive air conditioning systems employ some sort of pollen filter in the heater system. This not merely helps clean the air entering the cabin, it also assists in maintaining the evaporator free from debris and leaves. It always takes the proper execution of a report element-type filter that ought to be changed at the manufacturers recommended interval.
Lastly, as the evaporator is definitely wet as I described earlier, it is not uncommon for bacteria to begin to build up on the damp surface, causing a rather musty smell. This is often avoided by the standard utilization of an anti-bacterial agent applied in to the heater system which keeps the air conditioning components in the cabin clinically clean.
I really hope it has lifted the mist surrounding the operation of the air conditioning system in your automobile and has given you more of a notion of the maintenance that is probably be required. Remember that most personnel working on air conditioning in the UK should have a nationally recognised qualification, so make sure that a person with whom you trust your automobile is qualified to carry out the work.