Solar panels can be one of two types:

• photo-voltaic modules that generate electricity
• thermal collectors used to heat water

PV Modules

Photo Voltaic (PV) modules (aka panels) are a packaging of an interconnected assemly of PV cells, also called solar cells. These cells are ganged together to create a higher voltage of direct current (DC).

Thermal Collectors

A solar thermal collector is designed specifically to generate and capture heat, generally in the form of air, or liquid, such as water, glycerin or alcohol.

Thermal collectors are generally used for heating space or water.