The present invention relates to an energy transforming device comprising a radiation source (2) arranged to emit electromagnetic waves in a field of propagation a source irradiator (3r 2f) arranged to provide electromagnetic waves towards the radiation source (2), and a voltaic element (4) arranged to convert electromagnetic waves into electricity, wherein the voltaic element (4) is positioned in the field of propagation. The present invention also relates to a tanning bed (1) comprising such energy transformation device.
