Positioning Solar panels.
The direction and angle that your panel faces can have a big impact on it's performance by affecting the amount of light that hits the panel each day through the year. Some solar panels move continiously to track the sun but most will not go to the expense and difficulty of implimenting that. If your one of the majority, that are going to fix your panels in one place, then you have to get it right first go.
To get it right we have to make sure that the panels get hit by the maximum amount of light. This happens when the sun is directly above the panel.
As you can see from above, the angle that the sun hits a panel changes the ammount of exposure. At 30 degrees from the panel, the panel is only exposed to 50% of the light of the sun, at 60 degrees, 87% and at 90 degrees, 100%. This happens because the sun emits the same number of photons in a square cm, but once we put our panels on an angle, those photons are spread across a larger area.
As we all know, at different times of the day the sun moves through the sky and so any stationary panels get exposed to differnet angles, so what is directly above at one time of the day will not be at the next. What you might not know through is when the sun it at it's highest it is not nessisarly straight up, but may be off by an angle. And that angle is different at different times of the year and different at different latitudes. This angle is to the south in the northern hemisphere and the north in the southern hemisphere.
So we need to take all of this into account. Luckily what is good for your neighbour (aka your rough latitude), is good for you too. So below is a table that will show you what angles to hav your panels on, at different latitudes, at different times of the year.
The angles expressed in the table above are represented by A in the diagram, and the direction to the South or North, eg 90 degrees is perpendicular to the ground. So for example, in Sydney at 40 degrees latitue, we have the angle to put the panel on each month. If we wanted to set it in place for the whole year we might want to average these figures to put your pannel facing north at an angle of 60 degrees.
There are also a few different easy things we can do to improve the exposure of our panels. While constant tracking is complicated, it is easy to move your panels once or twice a year. We can adjust the angle of our panels to have two settings and in summer or winter adjust the angle to get the best of the availible light. So, if we look at our sydney example from before, we can break the year into two and take two averages. That way, in Sydney, we can have our panels at 75 degrees, North facing in the warmer months and 45 degrees in the colder months. And, that should be all you need to know!
If your not sure what you latitude is or you would like to work it out yourself, here is a good method for you.
You will need two pieces of paper, some sticky tape and a pen. First cut out a strip 10cm long and 2 cm thick and fold it in half. Sticky tape this to one side of the paper in roughly the spot of the black stick on the above picture. Now all you have to do is put this out in the sun and every hour or two place a mark where the shadow reaches. Connect these dots into a smooth curved line. Fine the shortest place from the line to the center stick and measure the distance, lets call this distance X. Now the best angle for that time of the year is given by inverse sin of 10/X. Pop it into your calculator and set your panel at that angle. and it should be good for that time of the year every year.
After all this, you should now be getting the most from your panels!