In light of the expected phase-out of refrigerant 134a, the Gas Review reports that support has emerged for the use of HFO1234yf as a replacement refrigerant gas.

As a number of potential replacement products are considered, 1234yf has been largely heralded as the most probable refrigerant alternative in respect of its convenience of use and considerable success under testing so far.

A post-134a market seems imminent, as tighter legislation leans towards the phase out of this environmentally-unfriendly refrigerant and new alternatives are encouraged.

Changing market
An EU policy implemented in 2006 will soon be applicable to vehicle manufacturers in Japan, determining that no refrigerants with a Global Warming Potential (GWP) of more than 150 will be permitted for application in new car models. This will be banned from 2011, while a phase out restriction will be applied to other non-new vehicles and a complete ban is to be realised by 2017.

Such legislation effectively spells the end of the road for 134a in this application, as a GWP of around 1430 renders it far too environmentally ugly as a car air conditioning refrigerant.

This has initiated the development of other replacement products, with three types of replacement thought to be in the front running as the leading substitute products.

Decisive factor
Of the three alternatives that have been chosen, notably CO2, HFC152a and 1234yf, these have all undergone both examination and evaluation by vehicle and air conditioning system manufacturers from around the world, as well as the automobile industrial associations from countries around the world.

German firms including BMW and Volkswagen are thought to have persisted in their recommendation of CO2, while the existing manufacturers of 134a have strongly recommended fluorinated refrigerants such as the proposed 1234yf.

At a ‘Phoenix meeting’ titled SAE 2008 Alternative Refrigerant Systems Symposium held in Arizona in the US by the Society of Automotive Engineers (SAE), a Honeywell/DuPont joint collaboration announced the development of 1234yf. Two or more vehicle manufacturers are believed to have since evaluated the gas as the ‘most environment-friendly refrigerant at the present stage’.

The outcome of an outstanding toxicity test is yet to be known, which had been due to be made public in September (2008). If successful in its findings, the new gas could be all set to emerge as the most prospective candidate for replacement.

In many ways, this is already thought to be the case. The product has a significant advantage of its rivals.

If CO2 were to be used as a refrigerant, a high pressure of 5-10 times that of the existing 134a would be required for optimum cooling performance and in turn, so would a revision to system components to reinforce these and ensure they are capable of withstanding higher pressure. With this, comes a complete re-design of systems and overall added weight.

In contrast, 1234yf would be capable of easy insertion into existing systems and would negate the need for re-design and production. It would be a simple ‘drop-in’ replacement applicable to any existing air conditioning systems with 134a specifications.

Some concerns over flammability and toxicity still exist, though these have largely been disregarded by testing to date and the forthcoming results of the final toxicity tests could dispel such fears altogether.

The Japan Automobile Manufacturers Association (JAMA) disclosed in July that it was carrying out its own evaluation of the use of 1234yf, but indicated that so far it sees the proposed gas as the more environment friendly of the alternatives.

For the prevailing product, it seems a lucrative market beckons. In the almost 18 years since a sample of 134a was introduced to the market as the replacement for the polluting CFC12, despite the many twists and turns of product replacement there is currently a global market of Y80bn – or 160,000 tpy.