If you have done so, you may also have noticed:
- patent claims by at least two persons/companies
(meaning: nobody will help you copy their design)
- a scarcity of actually working plants
- a lot of marketing hype. The vocabulary used is uncomfortably close to water and vortex mysticism (
http://en.wikipedia.org/wiki/Viktor_Schauberger) and green/environmentalist dogmatism (like "only micro hydroelectric power is good hydroelectric power").
- Everybody in the field is looking for investors.
There´s one (imho fairly reliable) third party report of ~40% hydraulic efficiency (~25% over all) for a comparable design here:
http://web.fhnw.ch/technik/projekte/eit/Herbst2010/CerGaf/ergebnisse.html
So claims of >80% hydraulic efficieny are ... remarkable.
Have you tried the Swiss cooperative?
http://www.gwwk.ch/
The German wikipedia page has a few more links but nothing really new.
http://de.wikipedia.org/wiki/Wasserwirbelkraftwerk
If you really want to design: the turbine works like an inverted centrifugal pump. Get yourself some CFD code for a centrifugal pump and start modifying.