Valeooscope - Air Conditioning System Thermal comfort loop

11. The components of the A/C Loop

11.2 A/C loop lubrication Oil circulates throughout the whole A/C loop: g Compressor g Condenser g Expansion valve or orifice tube g Evaporator g Receiver drier or Accumulator The oils used in air conditioning fulfill the following functions: g Lubricating the compressor g Cooling the compressor g Improving the sealing of the compression parts g Expelling impurities from the loop by circulation g Improving the sealing of the joints in the loop The two main families for the automotive air conditioning market are: g Synthetic Polyalkylene glycol oils (PAG) g Synthetic Polyolester oils (POE), used for electric compressors in hybrid vehicles. 11.2.1 Oils and compressor technologies Mechanically driven compressors g 3 types of synthetic oil g All Polyalkylene glycol (PAG) g ISO46 - ISO100 - ISO125 Electrically driven compressors g 1 type of synthetic oil g Polyolester (POE)

11.2.2 Oil and refrigerant types

The traditional oil for R134a applications cannot be used for the new HFO1234YF refrigerant. A new generation of PAG oil has been developed to be compatible for both uses. Oils are hygroscopic (readily absorbing moisture from the air). The mix of humidity, refrigerant and oil produces Therefore it is essential to extract these acids and other residues in regular maintenance operations and to renew the refrigerant and the oil. Similarly, bottles of fresh oil, and any other contai- ners, must not be left open or they will absorb humidity themselves. acid matter in the air conditioning loop. Over time, these acids corrode the circuit.

11.2.3 Oils in the catalogue

The volume and viscosity of the oils to be used are shown in the table of vehicle products.

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