In scientific terms, (solar) photovoltaic is the transmutation of atom particles from light to electricity.
In simpler terms, natural daylight is absorbed by an intricate system of PV cells, this is passed to the inverter and converted to usable power and distributed around the home for use. But how? How does all this work?
A solar panel is built up of cells, a typical 1m x 1.68m solar panel comprises of 60 cells. Each cell is connected via a complex circuit of wires and held together by an aluminium frame. The performance of solar cells is measured by its efficiency e.g. the efficiency of converting natural daylight into electricity. As only a percentage of natural daylight is absorbed and converted into electricity a standard cell on a 250w panel would reach between 13 and 17% efficiency.The panels are then formed to create and array and installed (ideally) on a south facing roof.
The panel cells are manufactured from silicon based material. There are two main layers to each panel, when natural daylight hits the panel a chemical reaction occurs, in the top layer negative charges are produced and in the bottom layer a positive charge is produced. When the two layers meet in the middle this is when the DC current becomes apparent. It is this DC current that is pushed to the inverter.
The heart of your PV system is your inverter; essentially this does all the hard work. Your home runs off AC power BUT your panels are producing DC power, so it is the job of the inverter to convert the generated power into usable power. But which inverter do you choose, well it all depends on the type of installation you’re having. With the amount of money you’re investing you want to make the most your of your system. Here are a couple of things you might wish to consider when choosing your inverter:
- Single roof installation: with this type of installation providing there are no shading issues a traditional string inverter would be suffice
- Two roof installation: splitting your panels over two roofs of a different angle or direction requires a dual tracker inverter. This allows each roof to work independently. For example, 6 x panels installed on a south roof and 6 x panels installed on a west roof – the panels on the west roof wouldn’t work as efficiently when the panels on the south roof are in natural daylight and vice versa. Therefore choosing a dual tracker inverter would allow each roof to work independently.
- Three roofs or more or shading issues: as above, if one roof is in daylight and the other in shade the panels with a traditional string inverter (or dual tracker inverter) would only work to the strength of the weakest panel, so to ensure all panels are working to their maximum output in these instances we would recommend optimisers or micro inverters.
Once the power has reached the inverter, it is very cleverly converted into usable AC electricity. The usable AC electricity is the passed via a PV cable into the main fuse box (consumer unit) for distribution around the home e.g. to power the washing machine, lights, TV etc.