|This solar water heating system is unique in that it uses a simple
tracking system to keep the collectors pointed at the sun all day.
Tracked collector systems are fairly common in PV systems, but rare in solar water heating systems. While there are some challenges to making this work, the benefit is an about 30% increase in collected heat over the course of a day.
Thanks very much to Lee for
sending this in!
Front view of the tracking collectors.
Rear view of the
tracking collectors. Note that the link behind the main support post
allows seasonal adjustment
of the tilt angle.
If a drain back system is used it is important to make sure the hose from the collector to the pex pipe going underground is always sloped downward-no matter what direction the array is pointing. I had some freeze up problems before I got it right. Rubber radiator hose works well and will not break if it does freeze. When I built my collectors I brought the intake and return lines out of the right corner of both collectors. This was a mistake. One collector should have been built with the lines coming out of the left corner. That way when they are setting side by side the lines can be connected together with tees and have a neater plumbing setup.
On the next array I set up I am going to change the design of the pipe support. Instead of having the pivot point half way up the collector I'm going to move it to the bottom. There will also be a second support higher up. The advantage of this is that I can eliminate the radiator hose. The water lines will come out of the collectors and tie directly into the underground pex pipe that will come up the support pipe that is cemented into the ground. I will use Sharkbite tees that will swivel as the array turns. I'll let you know if this works. I have the next two collectors built and will be setting them up during the next couple weeks as time permits.
This shows the linear electric actuator that is used to rotate the collectors for tracking. These actuators are
normally used to point the large TV satellite dish antennas, and are readily available at reasonable prices.
This is the tracker electronics. The basic tracker board is available from www.RedRok.com and is only about $35.
The RedRok site also has quite a bit of material on building simple and inexpensive tracking systems.
Gary April 29, 2010