I only saw the referenced article, and had the same question. Perhaps it has something to do with the densities produced by differing membranes???
Lawrence -----Original Message----- From: Michel Jullian [mailto:[EMAIL PROTECTED] Sent: Sunday, February 10, 2008 11:26 AM To: [email protected] Subject: [Vo]:Re: Ocean glider uses ocean heat differentials 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 ----- Original Message ----- From: "Robin van Spaandonk" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Sunday, February 10, 2008 12:40 AM Subject: Re: [Vo]:Ocean glider uses ocean heat differentials In reply to Lawrence de Bivort's message of Sat, 9 Feb 2008 11:08:28 -0500: Hi, [snip] > > http://news.bbc.co.uk/1/hi/technology/7234544.stm > >The heat differentials expand or constrict wax, which provides energy for >propulsion. > >Battery power needed to sensors and communications. It would seem trivial to include a small hydraulic motor driven by the expanding oil, which drives a generator to top up the batteries. Regards, Robin van Spaandonk <[EMAIL PROTECTED]>
