The first step in any solar system installation – after preliminary financial analysis, of course – is determining the number and arrangement of solar panels. As we show elsewhere, the size of the rooftop or land available for solar panels will determine the amount of electricity produced. But the arrangement of panels can be equally decisive.
The solar electricity production of solar panels is influenced by a number of key factors. These factors need to be evaluated by an engineer in designing your system. Bear in mind that they are not only important for sizing your system. They are also important to local building departments that must issue permits; after all, some rooftops may raise issues of wind sheet and so setbacks will be important to protect the system from being torn off your roof or land in strong wind gusts.
The arrangement may also have aesthetic issues for you and your architect. If the solar system will be visible from the street you may wish to examine closely the arrangement of panels to make sure that you are happy with their appearance.
IMPORTANT: Beware of engineers or solar contractors that try to maximize the size of the solar system without regard for aesthetic considerations. We have seen some cases of horrific installation where solar panels project beyond rooflines or are tossed together like an arugula salad.
In designing the layout of your solar panels two key factors will be taken into account. These factors are analyzed using widely available programs that determine the amount of solar electricity that can be expected to be produced as a result of the layout.
Azimuth. Azimuth measures the angle of the panels relative to the sun. Commercial rooftops are generally flat and so the azimuth will be the angle of the panels when installed on the roof. In the case of residential or rare commercial gabled rooftops, the angle of the roof will be important to assess.
Orientation. Conventional wisdom teaches that panels should be laid out on a north-south axis, angled (using a proper azimuth) toward the south. Historically most installers have chosen this orientation because the sun moves from east to west and it is logical to assume that the maximum insolation (exposure to the sun) will occur in this way.
Wrong. Recent research has indicated that an orientation that is more toward the southwest or west will maximize solar electricity production.
In conclusion, be sure to quiz your energy contractor or advisor on the optimal layout for your panels in order to ensure that you are getting maximum solar electricity production.