26 Sep 2003 wiggly   » (Observer)


On the subject of solar energy.

I am not an engineer or physicist but I know some basics so I'm not claiming to know everything here but just hear me out.

Let me firstly restate your idea in bullet form.

  • Place water in a vacuum sealed container.
  • Create partial vacuum to lower pressure.
  • Direct sunlight onto water vessel to heat it.
  • Since the pressure is now lower than normal the water boils at less than 100C.
  • Water vapour is directed to turbine to generate electricity.
  • Waste water recycled into cool vessel for reuse.

The problem as I see it is that your setup as described is self-defeating.

Firstly it will take energy to create the partial vacuum to decrease the pressure in the enclosed vessel. So you already have to create more energy than this for the system to generate a surplus of electricity.

Secondly if you lower the pressure to make the water boil at a lower temperature then you wouldn't be able to use the vapour to power a turbine. As soon as the water vapourises the pressure in the enclosed vessel increases and the vacuum pump will be working to draw it out of the vessel to maintain a lower pressure.

If you turn the vacuum pump off after creating a partial vacuum then the pressure will rise until the boiling point of the water is back at, or above, 100C.

Basically the vacuum pump renders the turbine inoperative because the turbine requires a positive pressure to move it, and therefore generate electricity. Whilst the vacuum pump is generating a negative pressure, and also using up electricity.


Wow, that sounds bad.

Since it sounds like you have pretty good access at your hosting provider how about a short-term fix?

You could use procmail and a list of email addresses to generate a whitelist program that will only let sender's you know to get through?

I was going to e-mail you but I figured you might not actually get it.

Also, I'm in the market for a good hosting provider so any and all suggestions to my e-mail address on my page please...points will be given for db access, custom perl libs, dns admin, good e-mail setup, IMAP servers blah blah blah...

Latest blog entries     Older blog entries

New Advogato Features

New HTML Parser: The long-awaited libxml2 based HTML parser code is live. It needs further work but already handles most markup better than the original parser.

Keep up with the latest Advogato features by reading the Advogato status blog.

If you're a C programmer with some spare time, take a look at the mod_virgule project page and help us with one of the tasks on the ToDo list!