This would indeed work Robin, but their system seems more complicated, the wax expansion energy is stored somehow according to the WHOI News Release here: http://www.whoi.edu/page.do?pid=7545&tid=282&cid=37008&ct=162
"The expansion of the warming wax converts heat to mechanical energy, which is stored and used to push oil from a bladder inside the vehicle's hull to one outside, changing its buoyancy. Cooling of the wax at depth completes the cycle." Michel ----- Original Message ----- From: "Robin van Spaandonk" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Sunday, February 10, 2008 11:24 PM Subject: Re: [Vo]:Re: Ocean glider uses ocean heat differentials In reply to Michel Jullian's message of Sun, 10 Feb 2008 17:26:12 +0100: Hi, [snip] >Quote from the link below: "Wax-filled tubes inside the craft expand when it >is gliding through warmer water. This heat is used to push oil from a bladder >inside the hull to one outside, changing its buoyancy." > >Anyone knows how this works in more detail? From the above description one >would expect the glider's buoyancy to increase when reaching the warmer >surface (same mass, increased volume), instead of decreasing as required for >diving. > >Michel The outside bladder must contain compressed air. When the oil compresses the air further, more volume is filled with oil, and less with air, so the average density is higher and the craft sinks. Regards, Robin van Spaandonk The shrub is a plant.
