Hi David - I left a reply on Talk:Focus-balanced paraboloid. Welcome. --Chriswaterguy 01:24, 5 July 2010 (UTC)Reply[reply]

Welcome![edit source]


Hi DOwenWilliams,

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Smart windows, etc.[edit source]

Answered at User talk:Chriswaterguy #Smart windows, etc. - redirect created. Thanks. --Chriswaterguy 06:11, 28 March 2011 (PDT)

Images[edit source]

Answered at User talk:Chriswaterguy #Heliostats image - thanks --Chriswaterguy 11:46, 12 June 2011 (PDT)

I saw your question at User talk:Chriswaterguy #Heliostats image; image was mine; you can find the 3D model via Google warehouse (type in "heliostat" or AT CAD Team") KVDP 01:47, 16 June 2011 (PDT)

I figured out, I think, that the image shows a heliostat (with a curious blue mirror) that is supposed to be operated by hand. But my immediate reaction was to ask "Why bother?". Thousands of years ago, the Egyptians used manually-moved mirrors for daylighting without constructing any kind of heliostat mechanism. Somebody, probably a servant, just kept an eye on the beam of reflected light, and when necessary adjusted the orientation of the mirror. The mirror was just propped against a rock, or something of the sort. (I've seen this being done in Egypt fairly recently. I was told that they were reproducing what the ancients did, and I have no reason to disbelieve them.) So what is "Appropriate Technology" about the thing you showed, when a simple rock is all that is needed?
Much more AT, in my opinion, are the clockwork devices that are used for solar cooking in India and other places in the developing world. A clockwork mechanism rotates a mirror about a polar-aligned axis at 15 degrees per hour to compensate for the movement of the sun in the sky. But I haven't found any nice public-domain images of any of them.
DOwenWilliams 20:15, 16 June 2011 (PDT) David Williams
No, you are misinterpreting the device. horizontal and vertical axis are motor-driven, and have a electronics system to change both alignments, allowing to track the sun without any human input.

KVDP 01:31, 18 June 2011 (PDT)

Ok. So it's just another heliostat driven by motors and electronics. So what's "AT" about it? Especially, what's AT about the image? The clockwork devices are much simpler. DOwenWilliams 07:44, 18 June 2011 (PDT) David Williams

Organizing content[edit source]


I'm letting you know that I'm working on cleaning up some of the great content that you left behind. I hope you can come and check it out! --Emilio (talk) 20:17, 18 February 2021 (UTC)Reply[reply]

Your 2021 impact stats are right here![edit source]

Let's recap.png

Hi David! We thought you may want know that your top performing pages so far are:

  1. Heliostats (18 545 page views) Update!
  2. Solar cooker (13 175 page views) Update!
  3. Sun related calculations (6 220 page views) Update!
  4. Smart windows (5 378 page views) Update!
  5. Pedal power (2 460 page views) Update!

Overall, your impact has been of 49,701 page views, woozaa!

Also, your user page has received 785 visits! People are interested in knowing more about you, edit your user page to tell the world what you've been up to.

Thanks for your contributions and for making Appropedia great, have a merry green Christmas!!

The Appropedia Team

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