Non-electric lighting devices or systems using daylight {characterised by the means for collecting or concentrating the sunlight, e.g. parabolic reflectors or Fresnel lenses with tracking means for following the position of the sun}
Non-electric lighting devices or systems using daylight {characterised by the means for collecting or concentrating the sunlight, e.g. parabolic reflectors or Fresnel lenses with tracking means for following the position of the sun}