flat-plate solar collector [1]
Device that collects solar radiation and heats a coolant, which in turn will be used in residential settings to heat water or the home.
frame 
Collector’s insulating case that is enclosed in glass.
coolant inlet 
Cold coolant flows into the circulation tubes to absorb the solar energy trapped by the collector.
coolant outlet 
The coolant exits the collector at high temperature (up to about 175°F) and is stored or used immediately.
glass 
Translucent covering (glass, fiberglass, polycarbonate) that allows solar radiation to pass through; the heat produced is trapped in the collector.
solar radiation 
All the electromagnetic waves emitted by the Sun.