The absorber is an extra wide variation on the PEX/aluminum absorber.
For more on the collector, including a link to Scott's site with all the construction details, and a few of my thoughts on the collector...
This is a good example of the kind of freedom to try new things and fit your design to your situation that building your own system gives.
Scott is a founder of the Yahoo SimplySolar group -- a good place to discuss your new solar ideas.
Gary