A TRACKING SOLAR CONCENTRATOR
SITING
Your tracking solar concentrator should be able to see the sun all day every day. That seems reasonable enough, but can't always be achieved. You'll notice in the cover photo of our prototype, it sits atop a sixteen foot tower. This tower tilts on a hinged base and can be lowered with a winch. We made it tilt because it was a developmental project that would see many tests and changes requiring easy access. It is mounted on the North side of the house and property lines made it impractical to go far enough North to be lower and still see over the house. The South side was impossible because of neighbors trees. This is an extreme situation and most sites we have examined would not require anything like this. Ultimately we moved it East about 80 feet on a seven foot non-tilting support and piped the hot water underground to a 1000 gallon energy storage tank
The sun at solar noon will be due South at an angle above the horizon equal to (90 degrees minus your Latitude) at the spring and fall equinox. As
we move through the summer and winter solstice the angle will vary above and below this point.
declination angle = 23. 45 sin 360 (284 + n)/365
where n is the day of the year beginning with Jan. 1st
My latitude is about 43 degrees, so at the equinox, March 21 & September 21 the angle at solar noon is:
90-43=47 degrees
and on June 21st, the longest day of the year, it is:
47+23 = 70 degrees
and on December 21st, the shortest day, it is:
47-23=24 degrees
You usually need the heat energy more in the winter, when the day is short, so the 24 degrees is the figure I was after. Find yours in a similar way. During the morning and in the afternoon the sun will be at even lower angles. If you want to get heavier into this, then you better get Duffie & Beekman. Check the neighbors shrubbery and its potential growth and select your location. Consider the problem of piping your heated fluid to its ultimate use point. As long as you don't need a tower, I suggest setting it atop a large pipe or pole buried in the ground. You might also consider a flat top roof. The weight, about 600 pounds will be perfectly centered on the mount, so the only tipping forces will be caused by the winds.
