ACR Journal

December 2021 | January 2022 REFRIGERANTS 16 Volume 8 No.1 Another regulatory consideration for this type of application is the Pressure Equipment Safety Regulation (PE (S)R), which is the UK legal requirement of the Pressure Equipment Directive (PED). Under PE(S)R, the low GWP A2L refrigerants (except R1234ze) fall into Fluid Group 1, which, compared to A1 refrigerants, lowers the threshold levels where more stringent safety requirements are needed. For example, consider a system with a 3-litre liquid receiver on the high- pressure side: If this system were operating with R404A, R448A or R449A, which are fluid group 2, it would be PE (S)R Cat I, which can be self-certified by the manufacturer without notified body involvement using industry-standard brazing qualifications. If a similar system were designed to use an A2L refrigerant such as R454A, R454C, R455A (fluid group 1) or high-pressure R744 (fluid group 2), then this would be PED category II requiring notified body approval for brazing, system certification, quality assurance procedures for production and pressure testing with witnessing of some system pressure tests also required. These increased requirements when changing from moderate pressure A1 refrigerants to either flammable or high-pressure A1 refrigerants are the main reasons it would not be practical to retrofit existing equipment to these products in the field. When designing systems with A2L refrigerants, it is advisable to minimise the refrigerant charge by minimising the size of liquid receivers and considering using microchannel condensers. This will minimise the risk and environmental impact, maximise the opportunities and reduce the regulatory requirements. The time for change is now! Whilst the availability of moderate to high GWP refrigerants is still good, it is easy to be lulled into the false sense of security that the time to change to low GWP options is somewhere in the future. However, systems that are being installed today run a very high risk of not fulfilling Figure 6 – C.O.P. vs R-744 at 15°C ambient condition. Figure 5 – COP vs R-744 at 32°C ambient design condition. their expected lifetime due to the choice of an unsustainable refrigerant. Low GWP refrigerants are readily available, and the availability of suitable equipment is rapidly increasing, meaning there is no reason why a sustainable low GWP can’t be installed today. In many cases, improved energy e ciency can be achieved using A2L refrigerants, lowering operating costs and reducing emissions for the expected lifetime of the equipment. It is human nature to try to avoid change, but this one is inevitable, so while there is still time, why not get ahead of the legislative curve and steal a march on your competition?