Photovoltaic system and is typically less useful than a calculation of return on investment. While it is typically calculated to be between 10 and 20 years, the financial payback period can be far shorter with incentives. Due to the low voltage of an individual solar cell (typically ca. 0.5V), several cells are wired "(also see copper used in PV systems)" in series in the manufacture of a "laminate". The laminate is assembled into a protective weatherproof enclosure, thus making a photovoltaic module or solar panel. Modules may then be strung together into a photovoltaic array. In 2012, solar panels available for consumers
Photovoltaic thermal hybrid solar collector (PV) panels. Heat is radiated from the panels into the enclosed space, where the air is either circulated into a building HVAC system to recapture heat energy, or rises and is vented from the top of the structure. While energy transfer to air is not as efficient as a liquid collector, the infrastructure required has lower cost and complexity; basically a shallow metal box. Placement of PV panels can be vertical or angled. A concentrator system has the advantage to reduce the amount of photovoltaic (PV) cells needed, such that somewhat more expensive and efficient multi-junction photovoltaic cells can be