| Article Index |
|---|
| How Does a PV System Work? |
| Things To Consider Before Installing |
| How To Estimate a PV System Size |
| Estimating the Cost of PV Systems |
| All Pages |
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How Does a PV System Work?
Photovoltaic (PV) power systems convert sunlight directly into electricity using photovoltaic cells, which are made using semi-conductor materials, which in turn are used to operate electrical appliances, computers, lights and other electronic equipment¹.
The photovoltaic cells are composed of two layers of semi-conductor material. One layer has a positive charge and the other a negative. When light enters the cell, some of the photons are absorbed by the semi-conductor material, liberating the electrons of the negative side of the cell to flow through an external circuit and back into the positive layer. This flow of electrons produces the electrical current.
To increase their power, dozens of PV cells are interconnected together in a sealed weatherproof package called a module. When two or more modules are wired together in series, their voltage is doubled while the current stays constant. When two photovoltaic modules are wired in parallel, their current is doubled while the voltage stays constant. To achieve the desired voltage and current, the installers wire them in series and parallel into photovoltaic arrays which can meet a wide variety of electrical needs¹.
A grid-connected PV System will require a utility inverter. This device will convert the direct current produced by the PV system to alternate current, which is required for loads such as radios, television sets, refrigerators, fans, etc.
For an off-grid PV system, consumers should consider whether they want to use the direct current (DC) from the PV system or convert the power into alternating current (AC). This conversion made by the inverter can consume up to 20% of all the power produced by the system.
