Not related to Vanagons except in the "useful for camping" sense...

"A Chinese peasant has made a solar water heater - using only beers
bottles and hoses."

http://www.ananova.com/news/story/sm_2850151.html

It's very nearly the most perfect invention ever in so many ways. A
cheap source of solar-heater water for showering, and the inventor "...
will build a public bathroom for the village using his invention when he
has the money to buy enough beers." What makes it so nearly perfect is
that any money you spend on beers can be expensed as cost of goods sold,
and the "manufacturing process" needed to convert beers into empty
bottles involves drinking those beers.

Maybe there's a way to make a Westy version. Hey Buese? You want to help
develop this into a product? You figure out from the photo how the rig
works. I'll start "making" beer bottles right away.

--
Mike "Rocket J Squirrel" Elliott
71 Type 2: the Wonderbus - for sale
84 Westfalia: Mellow Yellow ("The Electrical Banana")
74 Utility Trailer. Ladybug Trailer, Inc., San Juan Capistrano
KG6RCR