The report from UNEP’s Technology and Economic Assessment Panel (TEAP) will be submitted to this week’s Open-ended Working Group of the Parties to the Montreal Protocol in Geneva.
The 80 fluids have been proposed for testing or are being tested in industry programmes, are pending publication, or have been published in ISO 817 and ASHRAE 34 refrigerant standards. The report includes 15 new refrigerants added since the last TEAP report presented to November’s Montreal Protocol meeting in Dubai.
The majority of the refrigerants are blends, but traditional fluids are also included, along with just one new molecule. The new molecule is transdichloroethene, revealed by the Cooling Post as being used in a blend with HFO1336mzz(Z) being developed as an alternative to R123.
Of the 80 fluids, 11 are pure substances, of which 10 have been published in ISO 817 or ASHRAE 34, while of the 69 mixtures, 55 have publicly known compositions.
It is apparent that blends will play a major role in the future. Transdichloroethene is the only new molecule in the latest list but, being toxic, will probably only be used as a component in blends.
As long as vapour compression systems continue to dominate, engineers will probably need to come to terms with handling flammable, or “mildly flammable”, blends in the future. Research suggests that there is no new, safe, non toxic molecule waiting to be discovered. Last year an extensive study of over 150 million chemicals, screened more than 56,000 small molecules and found none of them offering better performance than those currently known.
However, despite the extensive list of potential new refrigerants, it is expected that future testing, development and commercialisation will decrease the number of viable candidates. Subsequent experiences from the market will likely further narrow down the number of viable lower GWP candidates in the future.