Ljusabsorbator

The present invention relates to a light absorber (1) which comprises an external material layer (2) of an at least partly transparent material and a space (5) through which a first gaseous medium is arranged to be circulated during heating by the light radiation which passes htrough the external material layer (2). The light absorber 81) comprises an internal material layer (4) arranged at distance from the external material layer (2), which internal material layer (4) comprises a material with radiation absorbing properties and constitutes at least one delimiting surface of said space (5), and means which is arranged to allow a natural circulation of a gaseous first medium, which advantageously is air, through said space (5).