Refrigerants, Oil

Refrigerants, oil





The impact of refrigerant on the environment
At the beginning of the 1930s it was believed that the perfect refrigerant had been discovered - different CFC components. Later research demonstrated that CFC (for example R12) severely affects our environment.
Due to this, a less aggressive refrigerant has been developed - different HFC compounds (for example R134a). In addition there are now a number of international agreements, national legislation and directives that govern the use of refrigerants.
Initially CFC compounds were called Freons. But Freon is in fact only the name of a product from a manufacturer.
Later there was international agreement about a R code for refrigerants. The letter R is for refrigerant and the number that follows it indicates the chemical compound.
The effect of refrigerants on the environment is usually listed in ODP and GWP.
ODP = Ozone Depleting Potential.
GWP = Global Warming Potential.






Note! The value R11 is used as the starting point to assess the effect on the environment. ODP and GWP for R11 are given as 1.

The ozone layer around the earth
Sunlight contains a lot of energy rich short wave radiation (ultraviolet radiation) which is damaging to all living cells. The ozone layer in the stratosphere, 15-40 km (9-25 miles) above the earth, catches almost 99% of the dangerous ultraviolet radiation.
The ozone molecule is unstable and consists of three oxygen atoms (O3). Ozone is consumed and renewed constantly, it is regenerated by sunlight.
Human emission of chlorine etc (which is in R12) breaks down the ozone layer quicker than it can regenerate. This leads to what are called holes in the ozone layer, which are in reality areas where the ozone layer is thinner.
Thinner ozone layers result in increased ultraviolet radiation which causes greater damage to all living cells, both animal and plant.
Some examples of this are:
- increased incidence of different forms of skin cancer.
- increased incidence of eye damage (for example cataracts and what is known as snow blindness).
- damaged vegetation (amongst other things worsened growth/harvests).
- damage to marine life (for example killing of algae, poorer quality vegetation and fish).

Green house effect
Sunlight which is a short-wave energy rich form of radiation reaches the earth. Most of the sunlight is reflected towards the earth and bounced back to space as long wave heat radiation. Some of this heat radiation is reflected back towards the earth by gases (= greenhouse gases) in the atmosphere. This phenomenon is usually known as the greenhouse effect.
The greenhouse has existed since the atmosphere was created and it this gives us a tolerable temperature on the earth. Without the greenhouse effect the average temperature of the earth would be approximately -18°C (0°F) instead of the present approximately 15°C (59°F).
The human way of life, in particular during the last 30 years, has considerably increased the emission of greenhouse gases into the atmosphere (for example carbon dioxide, methane, NOx, CFC).
This results in the gas layer in the atmosphere becoming thicker - and therefore more heat is reflected back to the earth, causing the average temperature of the earth to rise. In other words, the greenhouse effect is increased.
The consequences of an increased greenhouse effect are a subject of much discussion, but without doubt it damages the climate balance of the earth.

Different refrigerants, oils




A refrigerant needs to fulfill a number of important requirements. Amongst other things, it must be able to mix with oil and be non-corrosive. This is to provide good compressor lubrication and to prevent the metals and seals in the system from deterioration.
In older Volvo cars, R12 (CFC compound) is used as refrigerant. But in newer cars this has been changed to R134a (HFC compound) for environmental reasons. In addition, kits to convert and adapt older cars for R134a have been developed.
There is a decal on, or in the vicinity of, the receiver drier. The color of the decal indicates which types of refrigerant and oil the system is filled with.






Notes
1. PAG = Poly Alkaline Glycol Different PAG oil depending on the compressor. See the service literature.
2. Black = early version, Blue = late version.
3. Green = may only be used for S40/V40.

Caution! The correct refrigerant, oil type and seals must be used in the respective systems. Incorrect refrigerant and/or oil can result in the compressor overheating and seizing. In addition this can cause damage to hoses and seals.

Conversion from R12 to R134a, "Retrofit"





Conversion kit contents
The contents of the kit vary depending on the car and model year, but in all cases ester oil, a receiver drier and an expansion pipe or a TEV valve is included.
For certain cars, in addition to the basic kit there are also one or more supplementary kits (pipes, shaft seal for the compressor).
The cooling performance is unchanged by the conversion.

Why replace the oil and components?
Mineral oil which is used for R12 does not mix with R134a. Most of the mineral oil must therefore be replaced with ester oil. Ester oil can be mixed with both R134a and the remaining mineral oil in the system. In addition it has little effect on the material in the O-ring. As a result, only the O-rings on the connections that are opened in order to replace a component require replacing.

Note! On Sanden 508-510 and 709 compressors the shaft seal must be replaced with a seal adapted for R134a. This also applies when a replacement compressor is being used in a converted system.

The receiver drier must be replaced because:
- the drying agent intended for R12 becomes chemically unstable and breaks down if it is exposed to R134a.
- sufficient service life can be obtained (the old drying agent by may have consumed a quantity of water).
Expansion pipe/TEV valve must be replaced to obtain the correct flow of refrigerant (the molecules in R12 are larger than in R134a).