flat-plate solar collector 
Device that collects solar radiation and heats a coolant, which in turn will be used in residential settings to heat water or the home.
Collector’s insulating case that is enclosed in glass.
Cold coolant flows into the circulation tubes to absorb the solar energy trapped by the collector.
The coolant exits the collector at high temperature (up to about 175°F) and is stored or used immediately.
Translucent covering (glass, fiberglass, polycarbonate) that allows solar radiation to pass through; the heat produced is trapped in the collector.
All the electromagnetic waves emitted by the Sun.