A TRACKING SOLAR CONCENTRATOR
GENERAL DESCRIPTION
Teton Engineering's Tracking Solar Concentrator is an array of 116 mirrors, one square foot each mounted on a framework and arranged to reflect sunlight on a "collector", figure 1. The concentrated sunlight can raise the collector temperature to about 1200F, but we will run a cooling fluid, usually automotive type anti-freeze through it to absorb the heat just as it does in your car's engine. The heated fluid will be piped to a heat exchanger where it gives up its heat to another material such as the water you will shower with in the morning. The fluid, now cooled returns to the collector to be heated again and again. The possible uses are limited only by your imagination. We'll suggest some ideas in the chapters that follow, but the most obvious one is to preheat your domestic hot water before you run it into the big gas or electric hog that we call a water heater. Energy left over might be run through a genuine automobile radiator stuck in your space heating system or used to heat a basement or portion of the house that the central heat or stove can't reach.
The mirror frame and the collector will be assembled together with a "tail" that carries a counterweight atop a small tower or post set in the ground and equipped with a drive system that will automatically track the sun from sunrise to sunset. The whole business will weigh in around 600 pounds, but can be assembled in such a way as to never need more than two adults to put it together.
The array as shown in the cover photo is about 13 feet across. The four corner posts forming the pyramid to support the collector are about 10 feet long. The tower you see it mounted on is 16 feet tall, but is not typical of the usual mount. In most cases the array could mounted much closer to the ground.
The mirror array is mounted to the "hub" that contains the support bearings, the drive motor(s) and the simple mechanics for tracking the sun. There is two motor driven sub-systems. One periodically moves the array to follow the sun across the sky throughout the day. The other adjusts the tilt for seasonal variations
The electronic tracking system is the brains of our device and a brain that Teton Engineering is justifiably proud of. If you elect to totally discard the mechanical system in favor of your own design, you still have a bargain in purchasing this manual for the tracking system only. You may have seen other circuits published that look much simpler. They are! Because they are limited in various ways in which they respond to the whims of Mother Nature. Our circuit contains four op'-amplifiers (conveniently mounted in one package) performing multiple functions so that we can ignore wind, clouds and stray light sources. This is not just a fair weather machine, but rather one that you can turn on and forget. The electronic package also determines when the sunlight contains enough energy to justify operation of the circulating pump. It is also adaptable to many types of drive motors and can be operated on battery as well as commercial power
Every part in the electronic tracking system except the limit switchs is available at the nearly 8000 Radio Shack Stores around the USA. The parts can easily be assembled by the average hobbyist. A small module containing two photocells and two limit switchs rides on the mirror array where it can see the sunshine and sense the position of the array. The module is wired to a "control box" containing the electronics and relays to actuate the drive motor and fluid pump. The control box can be anywhere within a reasonable distance, preferably indoors.
