Figure 13 shows further system performance comparison from additional testing at the two A/C A and B cooling conditions using another 3-ton condensing unit with compact microchannel heat exchanger (MCHX) which enables significant 30-40% charge reduction, an important system design consideration, particularly for reducing the high cost of HFO refrigerant as well as further mitigating the risk with A2L mild flammability. However, it is interesting to note that R32 shifts further to the upper right quadrant while the other two HFO#1 and HFO#3 shift further to the upper left quadrant which suggests R32 is more optimized for smaller tubes (MCHX, 7mm, 5mm) while the HFO blends are likely better with larger 3/8” tubes due to their higher pressure drop. It was also noted that the system charge for these HFO blends is about same as R410A while R32 is 15% lower. This brings the question of how to integrate efficiency, charge, GWP into one comparison and the LCCP is the industry-recognized overall metric for that purpose.