Automotive Air Conditioning Facts:
If leaked or emitted into the atmosphere, the fluorocarbon refrigerant gas contained in most air conditioners and refrigerators can be extremely harmful to the environment. In particular, it can damage the Ozone Layer and contribute to global warming.
It is so serious in fact, that all 196 countries have signed an agreement called the Montreal Protocol, to agree to a world-wide phase out of ozone depleting substances.
The Australian Refrigeration Council (ARC) Licence scheme is the Australian Government's response to their obligations under the Montreal Protocol.
Did you know 1Kg of the commonly used refrigerant gas R410a, has the same greenhouse impact as two tonnes of carbon dioxide, which is the equivalent of running your car for six months!
That's why Australia has specific laws to help protect the environment and minimise any further damage to the atmosphere caused by refrigerant gas. And that is why the ARC Licence scheme is a vital to achieving a better quality environment for Australia.
Is it working?
Yes it is. In 2010 research from the National Institute of Water and Atmospheric Research in New Zealand recorded that the size of the Ozone Hole is the smallest it has been in the past five years.
Then, in May 2011 this encouraging news was backed up by environmental scientists at Macquarie University in Sydney, who have produced data that suggests the Ozone Hole is now recovering.
Both findings are directly related to initiatives such as the Montreal Protocol – which was the catalyst for the ARC Licence scheme.
There is a clear and present risk if consumers use non-licenced
technicians to install or service their air conditioners or
refrigerators - a risk to both the environment and their wallet.
Licenced technicians and authorised businesses have shown themselves to be qualified to do the job consumers have hired them to do. They have met the licensing/authorisation requirements under the Ozone Protection and Synthetic Greenhouse Gas Management Regulations 1995 and the fact that a licence holder must adhere to an Industry Code of Practice and possess the skills to do the job -minimises the risk of refrigerant emission.
Non-licenced technicians and businesses have not demonstrated their willingness to adhere to their legal obligations and this may reflect in their services. Consumers run the risk of:
- Sub-par service / installation which may mean additional services are required
- Risk of product warranty becoming null and void
- Risk of refrigerant leaking into the atmosphere - bad for the environment and bad for the performance of the system.
Benefits of the Australian Refrigeration Council.
As well as encouraging practices that benefit the environment, the ARC Licence scheme is 'good for business!’
When a business shows their RTA certificate or a technician presents their RHL card, this demonstrates a number of positive things to potential customers and the industry at large.
Firstly, it tells customers that the business or person they are dealing with is professional and qualified in their field of activity. This provides the customer with peace of mind. Secondly, the more licenced professionals in the RAC industry, the better the industry is viewed as a whole. This is important for the long-term sustainability of the sector. The ARC works hard to increase consumer awareness of the licence scheme and has developed an online industry directory for consumers to locate licenced professionals nearest to them, as well as numerous marketing materials for licenced and authorised businesses to use
How Air Conditioning Works:
conditioning like it says 'conditions' the air. It not only cools it
down, but also reduces the moisture content, or humidity. All air
conditioners work the same way whether they are installed in a building,
or in a car. The fridge or freezer is in a way an air conditioner as
well. Air conditioning is a field in it's own right, but we'll stick to
the main points or a car's air conditioning and the main parts used and a
few hints to keep the air-con system running properly.
Evaporation: You may have noticed that if you rub a little surgical spirits on the back of your hand, then your hand will feel cold. Why is that? It's evaporation. It is because the spirits on the back of your hand start to evaporate. As the spirit evaporates, it takes away heat from the surface of your skin.
Condensation: Have you ever noticed when you pour cold liquids in to a glass on a humid day that the outside of the glass foggs up and then turns into water well this is due to condensation
Heat of Compression: Have you ever noticed when you pump up a bicycle tyre with a hand pump, that the end of the pump gets hot? This is because the energy that you have put into the air by pumping it has not only compressed it, but has also caused the air molecules to push closer together so giving off heat with the friction.
Compression: At some point all gases will eventually become liquid. An example of that would be a can of deodorant - it's liquid inside the can (because you can hear it when you shake it) but is a gas when it comes out and hits your underarm. The pressure inside the can is higher, so the propellant inside is liquid.
Cooling by Expansion: Going back to the deodorant, you will notice also how cold it feels that's because the propellant has just expanded in volume quickly.
The important question is how does all this fit into making your car's vents blow cold?
Metal or alloy tubing and flexible rubber hoses connect all the actual components of the air conditioning in your car. Evaporation and condensation, expansion and compression are the physics of why it works. There are five main components to the whole system, namely the Compressor, Condenser, Receiver-dryer, Expansion valve or TX Valve, and the Evaporator.
Shown below is a diagram of an accumulated system with orifice tube.
How Air Conditioning Works:
The fluid that passes around the whole system is the refrigerant. The refrigerant can evaporate at a low temperature, and then condense again at a higher pressure. R-12 was the refrigerant used in almost all cars. It was widely available, however it was found to be a contributor to the hole in the earth's ozone layer as it was a chlorofluorocarbon (CFC). These refrigerants were discontinued, and all cars after 1994 use a non-CFC fluid called R-134A which is kinder to the environment.
So, here is how all the various parts of a car's air conditioning works:
Compressor: The compressor is the work horse of the air conditioning system, powered by a drive belt connected to the crankshaft of the engine. When the aircon system is turned on, the compressor pumps refrigerant vapour under high pressure to the condenser.
Condenser: The condenser is a device used to change the high-pressure refrigerant vapor to a liquid. It is mounted in front of the engine's radiator, and it looks very similar to a radiator. The vapour is condensed to a liquid because of the high pressure that is driving it in, and this generates a great deal of heat. The heat is then in turn removed from the condenser by air flowing through the condenser on the outside.
now liquid refrigerant moves to the receiver-dryer. This is a small
reservoir vessel for the liquid refrigerant, and removes any moisture
that may have leaked into the refrigerant. Moisture in the system causes
havoc, with ice crystals causing blockages and mechanical damage.
Expansion Valve: The pressurised refrigerant flows from the receiver-drier to the expansion valve. The valve removes pressure from the liquid refrigerant so that it can expand and become refrigerant vapour in the evaporator.
Evaporator: The evaporator is another device that looks similar to a car radiator. It has tubes and fins and is usually mounted inside the passenger compartment behind the fascia above the footwell. As the cold low-pressure refrigerant is passed into the evaporator, it vaporises and absorbs heat from the air in the passenger compartment. The blower fan inside the passenger compartment pushes air over the outside of the evaporator, so cold air is circulated inside the car. On the 'air-side' of the evaporator, the moisture in the air is reduced, and the 'condensate' is collected and drained away.
Compressor: The compressor then draws in the low-pressure refrigerant vapour to start another refrigeration cycle. The refrigeration cycle then runs continuously, and is regulated by the setting of the expansion valve.
The whole process is reasonably simple when explained like that. All air conditioning systems work on the same principle, even if the exact components used may vary slightly between car manufacturers.