A TRACKING SOLAR CONCENTRATOR
with an open end wrench and twisting the second with your torque wrench, while aligning the clip, to the point of destruction. Note that this torque limit is much higher than the previous one. With lessons learned, lets mount the clips without ruining any of the studs on the mirror array frame.
We have no good arguments as to which way to orient the clips, so do what pleases you. Figure 22 shows how we done it on the prototype, putting them crosswise to the rail they are mounted on. Run a small bead of silicon sealer on both edges of the mirror clip and mount the mirror. Be careful to center it in the clip, measure - don't guess or you'll be sorry when it comes to aligning (focusing) them. Don't be tempted to leave out the sealer. We have made controlled tests and found that the wind will make some of the mirrors walk right out of the clips if you depend solely on friction. It doesn't seem to make much matter what the orientation of the clip is, because they all move through vertical and horizontal positions throughout the day.
Go back and touch up the clip alignment to correct any mirrors that are not square with the rest. A recheck of the torque on all of them would be a good idea. Done this way, we have never had one come loose. 1999- this is still a valid statement, 20 years later.
Add weight to the tail to maintain balance You may have to remove the roller chain (301) bolts from the drum (105) to determine that the balance is OK.
MIRROR INSTALLATION- FOCUSING
This is the fun part, because now you will begin to appreciate the energy that you have at your command. We'll do this now, rather than after the collector is mounted as the dummy target Is expendable while the collector should be protected with fluid running through it. Mount up the dummy target, a scrap of sheet metal, 20 inches square on the collector frame (011). Paint it flat black with a heat resistant paint such as Derusto #760 barbecue black. This will reduce the reflections to help you avoid eyeball burnout.
The dummy target like the real one will cast a shadow directly into the center of the array. Locate this center, and make permanent marks on the rails (007) where the shadow must fall, figure 26. These marks can be seen in the cover photo and are used for the periodic adjustment of the tilt drive in normal operation, so make them visible.
