I had a short discussion with cheerio (in our forum) regarding some problems he was facing with a boost regulator, while out of the sudden an old member of the forum, George, posted a link to an excellent video with energy harvesting chips.
This long demo video explains how these awesome ultra efficient chips work. He also shows the list of Linear Technology energy harvesting chips and explains how to choose the proper product for your application. Finally, he experiments with the LTC3109 and the LTC3105.
I was astonished when i saw that the LTC3109 can operate with a voltage source as low as 20mV and produce a fixed output of up to 5V!!!