I'm having some trouble understanding why using a commercial product, BluTec copper, in a manner in which it is intend to be used (heating water via unconcentrated sun) is news? When you build a colar water heater normally you are working to not have it boil the water. It's more efficient not to. In fact the article even says they get better efficiencies when they-- get this-- run it below 100c. Wow! alert the media and publish it in nature.
So what they did was create a thermally insullated restricted flow system so the water super heats which is completely expected and precisely what designers expect and thus try to avoid in commerical systems.
Blutec solar heated are made in massive quatitites.
So can some one explain why this is news? I'm being serious not sarcastic.