How does Car air conditioning remove heat from a vehicle?

An automotive air conditioner system is composed of four basic parts - a pump, driven by a belt and called a compressor (to compress and ciculate gas), a radiator like unit known as a condenser to release heat and condense gas to a liquid, an expansion device, usually a thermal expansion valve (TXV) or an orifice tube (depending on the type 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.

A car air conditioner system is designed to extract excess heat from the air inside the vehicle and transfer it out of the vehicle, leaving only cooled or 'conditioned' air 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 conditioner service?

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

• Air vent temperature check

• Assess condenser temperature
  
  
• Check suction line temperature is correct
  
  
• Drive belt and pulley adjusted
  
  
• Operational check of thermostats and valves
  
  
• Ensure condenser fins are free of dirt or debris
  
  
• Inspection of components and hoses
  
  
• Evacuation and recharge of refrigerant (where required)
  
  
• Use electronic leak detector to test system lines and components for leaks

Why do I need a car air conditioner system service?

Checking or changing the oil level in the refrigerant can prevent the compressor seizing up. If the air filters are plugged with dirt and bacteria it will affect the performance of the entire system and it can even cause it to quit functioning completely. In addition to impacting air conditioner efficiency, dirty air filters can cause all kinds of health problems too.

Your vehicle air conditioner system must be checked for problems once a year for any signs of decay of the connections, hoses and seals to ensure refrigerant is not leaking over time. Regular service of your automotive 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 results in a reduction of fuel expenditure.

Why does the car air conditioner need to be serviced?

A car air conditioner system is designed to extract excess heat from the air inside the vehicle out of the vehicle, leaving only cooled or 'conditioned' air 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 mercy of the elements and very stressful operating conditions and being expected to function occasionally rather than being 'Always On' can cause issues with the connections, seals and hoses. Your 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. You can find out more about licensing on the Australian Refrigeration Council (ARC) Website.

What is responsible for the bad smell in car air conditioning?

The moist environment can support 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. While modern evaporator units tend to be more efficient, they have an increased capability to trap moisture and allow for micro-organism development.

Les Haldane Mechanical mechanics have the capability to use specialist ultrasonic technology to get rid of any micro-organisms that may cause unpleasant odours 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.