[Vo]:It's Alive!

[a.ashfield]

This paper that you can find from one of the links gives more details 
than I have seen before.
http://aromapress.com/~defkalio/wp-content/uploads/2013/01/ICCF-17-Hadjichristos-Technical-Characteristics-Paper.pdf
Seems they claim they can get a COP of 22