Do solar thermal receivers utilise only visible region sunlight for its purpose?

Question

Do solar thermal receivers utilise only visible region sunlight for its purpose?

Answer 1

A solar collector is designed to absorb all incoming electromagnetic energy.  Most of what it absorbs that isn't visible is infrared.  A glazed (covered by glass) collector traps infrared radiation, giving the collector more time to absorb it.  As you can see from the solar radiation charts in the reference, much of the incoming solar energy is in the infrared.

Answer 2

Hi. They are designed to focus a particular set of frequencies to the collector and I think infrared has to be included. Infrared is not visible.