Geoff Laughton presented this rocket stove
water heater in a video published May 12, 2013, that's true.
However, the guy who built it is someone else, his name is Tim Barker. He built this appliance and wrote an article published November 23, 2012 by Permaculture
Here's the article, complete with diagrams of its workings.
Tim built other water heaters
based on rocket stoves, notably in Missoula, Montana during the Innovator's Gathering 2014, to name one event.