In reply to David Roberson's message of Fri, 18 Jan 2013 17:03:07 -0500 (EST): Hi, [snip] >Robin, you are right, I was afraid that I would break that nasty thermodynamic >law and become confined within a black hole. > > >I was actually hoping that the solar cell argument would help me understand >why the heat engine limitations exist. Now, I am a bit confused. It is just >too easy to break that rule and get away with it. I was hoping for a good >challenge. > > >So why not just harvest the heat energy around us and have that perpetual >motion machine that we would all desire? All we have to do is to come up with >a process that converts the local IR into DC and be on the way. > > >Something is wrong with this picture unless the patent office needs to >reconsider their ban on patents that suggest perpetual motion. Maybe not >after a little consideration, sooner or most likely much later all of the >heat will be harvested and the patent office wins. No perpetual motion is >possible.
I think that the minimum energy that will activate a solar cell is in the infra-red, though it obviously depends on the bad gap of the semiconductor used. If you can get hold of one with a small band gap, it might make an interesting experiment to see if it gets colder in an insulated closed container while charging a battery. Regards, Robin van Spaandonk http://rvanspaa.freehostia.com/project.html
