Well you are looking at 24-48 kwh per day of use and the article says that the machine purifies ~250 gallons in that time. So approximately 10gph at 1-2kw.
Ideally, one only has to push the water back and forth over its phase boundary by an arbitrarily small delta-T, so the energy consumption can be arbitrarily small too. The 150 J/g is all heat leakage.
