Last column, I explained how a solar panel produces power and what kind of power it produces, but how do we assemble a system if we have more than one panel?
Multiple panels can be assembled into what are called arrays. Arrays allow for the panels to be connected together to generate more power.
Connecting the panels in series will allow the electrical voltage to increase; connecting the panels in parallel will bring the electrical amperage up. In this way, one can construct an array that will provide adequate power to maximize the energy gained from the sun.
Arrays need to be positioned to keep them off the ground, keep them pointed at the optimum angle for the best solar gain, and in our area should be adjustable to prevent snow from covering them in that all too familiar white season.
Mounts are designed for roofs, walls, on the ground, and the top of poles. Tracker mounts are a specialized type of pole mount that is designed to keep the array not only at the optimum angle, but to follow or “track” the sun across the horizon in its daily journey. Each mount has been developed for different areas or structures to meet all the diverse site configurations.
Whichever one is determined to suit your needs, they all have a couple of basic considerations.
The first is a clear view of the sky; the second is the angle of the sun in the horizon.
Here in Central Alberta, we are at 52 degrees latitude so optimum angle would be 35 degrees off of vertical during summer operation.
Winter, however, is a different matter.
With the sun low on the horizon and the ever-present threat of snow, a one-degree angle off vertical is more desirable. This angle keeps the panel pointed towards the sun, but it serves the added purpose of minimizing, if not eliminating snow buildup.
Solar panels will produce more power when it is cold, but not if they are covered in snow. How much more power? Typically a Suntech 280 watt 2 panel module will produce 56 volts at 35C and 117 volts DC (Voc) at -40C.
Using wall mounts, if there is an unobstructed view of the sun, is a good method of mounting an array, with pole mounts coming a very respectable second.
Don’t get me wrong — roof and ground mounts have their place.
But the ultimate mounting system is the tracker. Designed specifically to track the sun, these robust creations do their job well.
Some would argue that to make up for the cost, simply add a few more panels. It’s a valid argument, but with the long hours of sunlight in our northern locale, the tracker definitely has its place.
Prices for mounting systems vary from between a low of 75 cents and as high as $2.50 per array watt. Economical systems can be found to meet any budget and construction situation, and there is a mount that will serve the purpose no matter where the location.
Lorne Oja is an energy consultant, power engineer and a partner in a company that installs solar panels, wind turbines and energy control products in Central Alberta. He built his first off-grid home in 2003 and is in the planning stage for his second. His column appears every second Friday in the Advocate. Oja, who lives in west Central Alberta, can be contacted at lorne@solartechnical.ca