How does Car air conditioning cool the air in a vehicle?

An automotive air conditioning system can be broken down to four basic parts - a pump, driven by a belt, called a compressor (to compress and ciculate refrigerant gas), a radiator like unit called a condenser to remove heat and condense gas to a liquid, an expansion device, which could be a thermal expansion valve (TXV) or an orifice tube (depending on the type of A/C system used). Systems using orifice tubes also have an accumulator before the compressor to remove moisture from the refrigerant while TXV systems have a receiver-dryer before the evaporator to perform the same crucial task. Both the accumulator and receiver-drier are also used to store refrigerant.

Car air conditioning is designed to extract the heat from the air within the interior of the car and transfer it outside, leaving only cooled or 'conditioned' air behind to be recirculated. Hot air is passed across a gas filled evaporator, where the heat is easily absorbed by the refrigerant (in gas form), effectively removing the heat from the air in the car.

The now heated gas is pulled through the compressor where it is further heated (via compression). The next stage involves the refrigerant being forced through the condenser to quickly extract the heat from the refrigerant. The refrigerant, now condensed to a liquid, then moves through the expansion device (either a TXV or Orifice tube), which regulates the flow of refrigerant going to the evaporator, changing the high-pressure liquid to a low-pressure mist (gas). A fan blowing over the cold fins of the evaporator produces the cold air being blown into the car and the entire process then begins all over again.

What is included in a car air conditioning service?

A typical air conditioner service may include some of the following items;

• Check air vent temperature

• condenser temperature check
  
  
• Assess suction line temperature
  
  
• Pulley and drive belt adjustment
  
  
• Ensure that thermostats and valves are operating correctly
  
  
• Clean the fins of the condenser
  
  
• Ensure good condition of hoses and components
  
  
• Evacuation and recharge of refrigerant (where required)
  
  
• Use electronic leak detector to inspect system lines and components for leaks

Why do I need a car air conditioner system service?

The compressor needs the right amount of oil in the refrigerant to prevent it from seizing up. Should the air filters get plugged with dirt and bacteria it will affect the performance of the entire system and it can even cause it to fail to function completely. As well as impacting air conditioner efficiency, dirty air filters can cause all kinds of health problems too.

Your car air conditioner system ought to be checked for problems once a year for any signs of problems with the connections, seals and hoses to ensure the refrigerant has not leaked over time. Regularly servicing your auto air conditioner keeps refrigerant at optimum levels meaning the system does not need to work as hard and this in turn protects the system from damage and minimises fuel expenditure.

Why does the car air conditioner need to be serviced?

Car air conditioning is designed to extract the heat from the air within the interior of the car outside, leaving only cooled or 'conditioned' air behind to be recirculated. This is achieved using a special compound called refrigerant, capable of readily absorbing heat as a gas and quickly losing heat as a liquid.

Being exposed to the elements and very harsh operating conditions and being expected to run intermittently rather than being 'Always On' can cause decay of the connections, hoses and seals. Your car air conditioning system should be examined on a regular basis to ensure there are no problems or refrigerant loss due to failure or leakage from these points.

Simply by cooling the air in your car under normal running conditions, the filters of the air con get dirty and intermittent use can cause seals to dry and crack, allowing them to leak. Even without leaks, the gas in a car air conditioning system will eventually begin to degrade or evaporate over time and should be recharged where required to keep the air con system in peak running condition.

Can I service my own air conditioner?

Only qualified mechanics with the appropriate training should attempt to service a car air conditioner. Specific licences are required to be able to service or repair some types of car air conditioning systems, especially where regas (recharging of the refrigerant) is concerned. Strict guidelines and procedures must be adhered to when handling certain refrigerants, which must always be fully recovered and not allowed to escape into the atmosphere during servicing.

Refrigerant can also pose serious health risks if handled incorrectly. Specialist equipment is also required as the air conditioning system is under extreme pressure and must be pulled into a deep vacuum to remove any moisture, to avoid seriously damaging the system. You can find out more about licensing on the Australian Refrigeration Council (ARC) Website.

What is causing the bad smell in car air conditioning?

The evaporator core can be the perfect breeding ground for microbes, bacteria and even fungus due to the moist conditions found there. This can lead to nasty smells and possibly even be bad for the health of any vehicle occupants. While modern evaporator units tend to be more efficient, the addition of extra fins leads to an increased ability to trap moisture, allowing micro-organism development.

Drouin Auto Care mechanics employ specialised ultrasonic technology to ensure the destruction of any micro-organisms that may be causing bad smells or health concerns.

Just ask about our MIST service, which will kill any bacteria that may be lurking in your car’s air system. These bacteria can cause odours and even make you sick, especially if you have allergies or asthma. A MIST service doesn’t just make your car smell better - it makes it healthier for you and your family.