Submitted by: Charles Jackson

It’s August, the car is jammed with kids and luggage, and you’re finally on your way to the cottage. Suddenly you realize that your car’s air conditioning system is on the fritz, and your family vacation really starts to heat up.

Automotive air conditioning systems were first introduced in 1940 to address customer demands for relief from unbearable heat. These systems use refrigerant to cool the air and remove the heat from the car’s passenger compartment. Air conditioning also cleans the air that enters the car, and removes excess moisture as it dehumidifies the air.

There are three basic components to any automotive air conditioner system:

1. Compressor–Considered the heart of the air conditioning system, the compressor transfers and compresses refrigerant gas to let the heat out of the car.

2. Condenser–removes heat from the refrigerant and cools down the high-pressure gasses.

3. Evaporator–Acts as the heater core of the air conditioning system. The evaporator removes the heat from inside the car. The refrigerant then condenses the air and transforms it into water.

Cars manufactured in 1995 or later have been equipped with R-134A air conditioning system. These ozone-friendly units do not contain CFCs, are nontoxic and nonflammable.

Prior to 1995, automotive air conditioners came with R-12 refrigerant, most commonly Freon. During that time, a car owner experiencing air conditioner problems needed only to visit a local retailer to purchase a recharge kit. With a can of Freon and basic knowledge, the average driver could easily repair his or her own air conditioning system. When studies confirmed that R-12 systems were contributing to the damaged ozone layer, many countries including the United States banned their manufacture.

Common Problems

The most common complaint about automotive air conditioners, particularly R-134 systems, is the odor that permeates from the A/C vents. Mechanics and car manufacturers have concluded that accumulated bacteria and fungus in the evaporator core likely cause the odor. Because the air conditioning system is loaded with moisture, it attracts microbes. The solution offered by automakers is to make the blower motor effective in drying out the evaporator after the A/C system is turned off. General Motors introduced this breakthrough, called Electronic Evaporator Dryer.

This solution might offer relief to some car owners, but not to all. Installing this system can cost hundred of dollars. As a result, many car owners have resorted to finding alternative methods of fighting the odor. Using antibacterial chemicals such as Lysol can be an effective short-term solution. Keeping a can of Lysol handy can go along way for your odorous air problem. Just spay the Lysol inside the car, and in the air intake once a week, for temporary relief from the problem. Another way to help eliminate the odor is to shut off the A/C unit at least one mile before reaching your destination. This will allow enough time for the evaporator to dry out, essentially doing away with the moisture and microbes that cause odor. This can be the easiest and least expensive method in combating the issue.

Caring For Your A/C System

* To keep working efficiently, your automotive air conditioner must be recharged from time to time, depending on how often it is are used. Consult your mechanic or your owner’s manual for information about system recharges.

* Call your mechanic if you see water leaking from the A/C system’s condenser, as this can affect the refrigerant. Have the system repaired before refilling it.

* Replacing the filter once every three months will also help to maintain the performance of your automotive air conditioning system. This is where dust builds up when the A/C system is running.

* Setting the gauge at one specific temperature will also help it perform well. If you constantly switch from one temperature to another, your system will have trouble adjusting accordingly.

Automotive air conditioners can be a driver’s best friend, whether you’re traveling across town or from coast to coast. Keep your A/C unit well maintained, and keep your cool on the road.

About the Author: Charles Jackson contributes to several web magazines, on

recreation and hobbies

and

travel and recreation

subjects.

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Submitted by: P Hunter

Cooling is the transfer of heat energy via radiation, conduction or convection. But how does cooling really work in air conditioning systems.

Air conditioning cooling systems take advantage of a very clever physical law. When a fluid converts to a gas, it absorbs heat and conversely, when a gas converts to fluid, it releases heat.

Air conditioning systems use these principles over and over again to move heat from one location to another (e.g. from indoors to outdoors). In very simple terms, they use a closed loop of pipes to circulate a compound. Within this system is a compressor to convert the compound to a gas (therefore absorbing heat) and an expansion valve to convert it back to fluid (releasing heat). It s a little more complicated than that, but if you keep that simple concept in mind when reading the rest of this article.

Before we move on, just to let you know the compounds cooling systems use are known as refrigerants which have special qualities that allow them to change from fluid to gas (and vice versa) at much lower temperatures, thus better facilitating the cooling process. So here goes in a bit more detail:

1. When hot inside air flows over the cold, low-pressure inside evaporator coil (more commonly known as the inside air handling unit), the refrigerant inside absorbs heat and as it does so, it changes from a fluid to a gas.

2. To keep cooling efficiently, the air conditioner has to convert the refrigerant gas back to a fluid again. To do that, a compressor puts the gas under high pressure, a process that creates unwanted heat.

3. All the extra heat created by compressing the gas is then evacuated to the outdoors with the help of a second set of coils called condenser coils, and a second fan. As the gas cools, it changes back to a fluid.

4. The fluid refrigerant runs through an expansion valve, and in the process it evaporates to become a very cold, low-pressure gas. This is feed back into air handling unit and the process starts all over again.

It’s easy to see that there are two distinct things going on in an air conditioner. Refrigerant is chilling the indoor air, and the resulting gas is being continually compressed and cooled for conversion back to a fluid again.

Now lets look at the various components of a cooling air conditioner in more detail:

The compressor (which is controlled by the thermostat) is at the ‘heart’ of the system. It acts as the pump, causing the refrigerant to flow through the system. Its job is to draw in a low-pressure, low-temperature, refrigerant in a gaseous state and by compressing this gas, raise the pressure and temperature of the refrigerant. This high-pressure, high-temperature gas then flows to the condenser coil.

The outside condenser coil is a series of piping with a fan that draws outside air across the coil. As the refrigerant passes through the condenser coil and the cooler outside air passes across the coil, the air absorbs heat from the refrigerant which causes the refrigerant to condense from a gas to a fluid state. The high-pressure, high-temperature fluid then reaches the expansion valve.

The inside evaporator coil is a series of piping connected to a furnace or air handler that blows indoor air across it, causing the coil to absorb heat from the air. The cooled air is then delivered to the house through ducting. The refrigerant then flows back to the compressor where the cycle starts over again.

The inside Air handling Unit of an air conditioner contains the evaporator and a fan that blows air over the chilled coils and into the room. The outside part of the air conditioning unit contains the compressor, condenser and another fan to vent hot air coming off the compressed refrigerant to the outdoors.

In between the two sets of coils, there’s an expansion valve. It regulates the amount of compressed fluid refrigerant moving into the evaporator. Once in the evaporator, the refrigerant experiences a pressure drop, expands and changes back into a gas. The compressor is actually a large electric pump that pressurizes the refrigerant gas as part of the process of turning it back into a fluid. There are some additional sensors, timers and valves, but the evaporator, compressor, condenser and expansion valve are the main components of an air conditioner.

Described above is a conventional setup for an air conditioner and it is known as a split system.

About the Author: Peter Hunter is a Director at

Air Intelligence Ltd

. With 25 years expereince, they are leaders in the provision of commercial air conditioning and commercial heating through London and the Home Counties. Locationed in Berksire (see

Air Conditioning Berkshire for details

)

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