In recent years there has been increasingly serious concern about the thinning of the earth's protective ozone layer. It is a well-publicised fact that Chlorofluorocarbons (CFCs) and, to a certain extent, hydrochlorofluorocarbons (HCFCs) are responsible for a great deal of that damage.

Even if production and use of CFC fluids were to cease today, their effect on the ozone layer would continue for hundreds of years, due to their long residence time in the atmosphere.

In 1987, at Montreal, a protocol was signed by over 70 countries, committed to phasing out the use of CFCs by the end of this century.

This treaty had far reaching implications for industry, with refrigeration and air-conditioning manufacturers amongst the worst affected, as CFC refrigerants account for one-third of all CFC consumption.

The major chemical companies who produce CFC fluids responded quickly to identify a new, ozone friendly alternative - a Hydrofluorocarbon known as HFC R134a. HFC R134a has zero effect on the ozone layer and is readily degradable. Compared to CFCs, it has one-tenth the atmospheric lifetime, and one-tenth the effect on global warming of CFC 12.

Nevertheless, it has caused a major headache for refrigeration system manufacturers because the mineral oil lubricants, traditionally used in
refrigeration compressors, are immiscible with the new HFC R134a, a problem that has since been solved by Castrol, the world leading lubricants company.

The 'Castrol Retrofill Procedure' for industrial refrigeration has proved to be a most practicable and economical approach and has been widely adopted by the refrigeration industry.

During the Retrofill procedure, the compressor is isolated from the existing CFC system, drained of oil, and filled with Castrol Icematic SW. As Castrol Icematic SW is entirely miscible, the system can then be run effectively, using the CFC refrigerant to flush the remaining mineral oil back to the compressor sump.

Through repeated oil changes with Castrol Icematic SW, the residual mineral oil contamination is reduced to the recommended level of below 1%. Even a sizeable refrigeration system has been found to require only three oil changes before being ready to accommodate the new ozone friendly refrigerant HFC 134a. The only equipment change required using Castrol's Retrofill procedure is a new expansion valve.

As no expensive hardware changes are required, conversion of existing equipment using the 'Castrol Retrofill Procedure' will save industry millions of pounds.

Retrofill is also environmentally friendly as it totally eliminates the traditional need for a solvent flush using CFC 11, helping prevent further damage to the earth's protective ozone layer.

Castrol can claim one of the first successful conversions to an ozone-friendly system in the world - on an organic dairy-farm in the UK. Also, a supermarket chain has successfully Retrofilled its bulk food chillers and a major brewery has successfully completed the conversion of a large beer cellar.

The impact of Retrofill is so significant that Castrol have applied for a patent on the process.

Castrol has also developed a simplified procedure for the Retrofill of automotive air conditioning and other systems which do not have compressor isolating valves.

Castrol have supplied compressor lubricants to the refrigeration industry since the 1940s.

In at the start of ester technology, leading in product performance, we are committed to service the refrigeration industry with the highest quality compressor lubricants available today in order to ease the transition to environmentally friendly refrigerants.

Castrol offer a full support package to customers, including technical assistance and routine returned oil analysis. Located in over 45 countries worldwide and with a distribution network in place in a further 100 countries, our companies are ideally placed to support the international refrigeration industry.

Supplied in road tank wagons, ISO tanks, 205 litre non-returnable mild steel drums, 25 litre, 4 litre and 1 litre packages, Castrol Icematic SW can be ordered from any Castrol office and our representatives will be happy to provide advice and assistance relating to the Icematic SW series - the refrigeration lubricants that won't cost the earth!

In 1988, in close co-operation with leading compressor manufacturers and refrigerant gas suppliers, Castrol began developing and testing a new generation of HFC compatible synthetic lubricants.

Initially, the programme concentrated on synthetic oils based on Polyalkylene glycols (PAGs) which are commonly used in air compressors. However, Castrol quickly identified the limitation of PAG oils and centred its development effort around new synthetic ester technology.

From synthesis of novel polyol ester base stocks, a new range of lubricants have been developed that are universally miscible with CFC and HFC refrigerants, as well as HFC R134a - the Castrol Icematic SW series of refrigeration compressor lubricants.

Formulated using a highly effective, low treat and ashless additive package designed to reduce component wear, improve hydrolytic stability, and inhibit copper plating, Castrol Icematic SW grades provide important performance benefits over products without additives. They are also completely wax free and have very low pour points to prevent blockage and to ensure clean evaporator performance.

Castrol Icematic SW represents a truly versatile range of lubricants, compatible with both large industrial systems and small domestic units. In trials, Castrol Icematic SW has performed successfully over a wide temperature range; spanning a unique range of viscosities - from ISO 10 to ISO 350, thus enabling the lubricants to be used in all compressor applications ranging from 2hp up to 2000hp.

Before Castrol developed a multi-compatible lubricant, manufacturers and suppliers were recommending that users either switch to the ozone-depleting HCFC R22 as an interim measure or replace their existing R12 systems with entirely new equipment filled with HFC 134a. Both these processes entailed costly equipment changes, requiring at least a new compressor and condensing unit.

The unique properties of Icematic SW have enabled Castrol to pioneer conversions of existing CFC and mineral oil equipment to R134a and Castrol Icematic SW, with a minimum of expense and disruption - through a process called RETROFILL.

Lower Critical Solution Temperature (° C)