© RACA Journal www . refrigerationandaircon . co . za RACA Journal I April 2025 7
Associations
THE JOURNEY TO A BETTER WORLD :
A REFRIGERATION PERSPECTIVE ( PART 4 )
By Andy Pearson , Star Refrigeration
RACA Journal is providing the entire presentation in four sections . This is Part 4 of a four-part series .
It should also be noted that different PFAS transition into different sink chemicals . R-1234yf , the most common replacement for R-134a , widely used in mobile air-conditioners and large water chillers , is converted almost 100 % to trifluoroacetic acid , but its isomer R-1234ze is more likely to form calcium fluoride , a common and non-toxic mineral which occurs naturally in fluorspar crystals . There is therefore a case for switching R-1234yf uses to one of the R-1234ze isomers , although they require larger compressors for a given cooling duty . R-1234ze ( E ) would be a suitable alternative to R-1234yf , with a very similar normal boiling point , but would require a 30 % larger compressor . R-1234ze ( Z ) has a much higher normal boiling point and also much higher critical temperature so it is not currently used as a refrigerant but it might find a place as an alternative working fluid to R-245fa in organic Rankine cycle systems , or in high temperature heat pumps . The four substances are compared in Table 3 , which gives the normal boiling point and the critical temperature .
Table 3 : Key properties of Various Fluorinated Refrigerants
Refrigerant |
NBP (° C ) |
Tcrit (° C ) |
Pcrit ( bar ) |
R-134a |
-26.1 |
101.1 |
40.59 |
R-1234yf |
-29.5 |
94.7 |
33.82 |
R-1234ze ( E ) |
-19.0 |
109.4 |
36.35 |
R-1234ze ( Z ) |
+ 9.8 |
153.7 |
35.31 |
If concessions from the PFAS regulations are not granted for R-32 or the isomers of R-1234ze then it seems likely that the use of fluorinated refrigerants will continue to be increasingly restricted over the next few years . There will then be very few alternatives in the sectors identified earlier as the most difficult to adapt .
If hydrocarbons are to be used to fill the gaps when R-410A , R-32 and R-1234yf are tightly constrained then there is an urgent need for all relevant sectors of the industry to learn how to use them appropriately and safely . This is a multi-faceted problem covering component design , system construction , operation and maintenance . It also requires a substantial overhaul of our existing safety standards to reflect the real hazards that will be created by this move and to ensure that safety Dr Andy Pearson . is not compromised . There are already many stories of accidents , injuries and death related to the inappropriate use of flammable refrigerants in the commercial sector although it is perhaps fair to say that most of these , if not all , have occurred through ignorance of suitable procedures or malpractice that would not be sanctioned by a competent safety standard in any case , no matter which refrigerant was being used .
Safety standards such as ISO5149 , ASHRAE Std15 and EN378 have traditionally used two methods to promote safe system design :
• The first method , prompted by product standards for air-conditioners , retail equipment or other items , is to place a strict limit on the amount of refrigerant that can be contained within a unit in a certain location . Typically , this is governed by the volume of the space in which the unit is located and the characteristics of the refrigerant , either in terms of flammability or toxicity .
• The second method , more common for large industrial systems , is to recognise that limiting the amount of refrigerant is not the prime method of ensuring safety and other design features such as gas detection , emergency ventilation , operational procedures and staff training need to be implemented to keep staff safe in the event of a leak .
© RACA Journal www . refrigerationandaircon . co . za RACA Journal I April 2025 7