*** This argument is based on a study from 2011 which highlights an empirical correlation between the concentration factor of the separation process and the second law efficiency. However, there are some flaws in this analysis: 1) the number of data points in the empirical correlation is limited, 2) the correlation is not very strong, 3) the concentration factor for DAC extrapolates beyond any points in the data set, and 4) the analysis is agnostic of the technology. Email: jpy1@hw.ac.uk RCCS, Heriot-Watt University