SAE International’s research group reports Mexichem’s AC6 blend, based on HFO 1234ze and CO2, ‘offers risk profile equal or better than HFO 1234yf in all respects’.
The Co-operative Research Programme put together to investigate the potential of blended refrigerants to meet for the MAC directive has released its latest report, confirming that the AC5 and AC5 blends from Mexichem continue to offer potential as an alternative to HFO 1234 yf.
The CRP said that it had elected to publicise its latest results, where more in-depth research into the two blends confirmed previous findings, to add to the current debate over low-GWP alternatives for the MAC directive.
Specifically, the CRP said it ‘wanted to ensure that information that it has generated regarding the performance, flammability and risk assessment of these low GWP blended refrigerants is available to be included in the important discussion regarding replacement of MAC system refrigerant. Based on a detailed fault tree analysis AC6 offers a risk profile that is equal to or better than that of R1234yf in all significant respects. AC5 is comparable to R1234yf.’
The AC6 blend, which distinctively contains CO2, has a GWP of 130, compared to HFO 1234yf’s GWP of 4. I The blend has been found to have an ‘extremely low level of risk for vehicle operators and repair workers’, the CRP reported. It has zero flammability under 50 deg C, but is set to be classed in the A2L flammability category. The CRP said it agreed to validate the refrigerant based on lower flammability than HFO 1234yf and potentially greater capacity.
The final phase of its testing will see further assessment of heat exchanger optimisation and hose materials, together with physical testing of service and filling procedures.