How does a car air conditioner extract heat from a vehicle?

A car air conditioning system could be seen as having four basic parts - the compressor, a belt driven pump to compress and circulate gas, the condenser to dissipate heat and condense gas to a liquid, an expansion device, called an orifice tube or a thermal expansion valve (TXV) (subject to the kind of air conditioner 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.

An automotive air conditioner is designed to remove the heat from the air within the interior area of the car and transfer it out of the car, leaving only cooled or 'conditioned' air behind to be redistributed. 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;

• Confirm air vent temperature is correct

• Test condenser temperature
  
  
• Confirm suction line temperature ok
  
  
• Ensure correct drive belt & pulley operation
  
  
• Check correct operation of valves and thermostats
  
  
• Undertake cleaning of the condenser fins
  
  
• Assessment of component and hose condition
  
  
• Evacuation and recharge of refrigerant (where required)
  
  
• Check system lines and components for leaks

Why do I need a car air conditioner system service?

Seizure of the compressor can be avoided by checking or changing the oil level in the refrigerant. If the air filters are choked with dirt and bacteria it will affect the performance of the entire system and it can even cause it to break down completely. Aside from inhibiting air conditioner performance, dirty air filters can cause all kinds of health problems too.

An air conditioner needs to be checked for problems yearly for any signs of issues with the connections, hoses and seals to ensure refrigerant levels have not diminished over time. Regular service of 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 reduces the amount of fuel being used up.

Why does the car air conditioner need to be serviced?

An automotive air conditioner is designed to remove the heat from the air within the interior area of the car out of the car, leaving only cooled or 'conditioned' air behind to be redistributed. 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 mercy of the elements and very difficult operating conditions and being operated occasionally rather than being 'Always On' can have a detrimental effect on the seals, hoses and connections. A vehicle air conditioner 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.

Charnock Motors can arrange Air Conditioning Service with a Licenced Technician. You can find out more about licensing on the Australian Refrigeration Council (ARC) Website.

What causes a bad smell in car air conditioning?

The moist environment can promote the development of bacteria, microbes and even fungus growth inside the evaporator core. This can lead to nasty smells and possibly even be bad for the health of any vehicle occupants. Although modern evaporator units tend to be more efficient they have more fins, meaning an increased capability to trap moisture and allow for micro-organism development.

Charnock Motors mechanics can use specialised ultrasonic technology to eliminate any micro-organisms that may cause unpleasant 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.