The article "A Systems Approach to Remote Light Sources" describes the use of a reflector distribution system in a hospital [Borg, 1994]:
If the purpose is to move light without providing illumination at the same time, a reflector-based system may be cheaper and more efficient. Since the sulfur lamp provides extremely stable light from a point source, an efficient reflector in the lamp unit can "collect" the light into a narrow beam that moves from the lamp, via reflectors placed outside the lamp unit. If the air is clean, very little light is lost between the lamp unit and the reflectors.
At the University Hospital in Lund, Sweden, the sulfur lamp is being used in combination with reflectors made of microprismatic optical materials. This hospital, typical of those constructed during the building boom in the Nordic Countries in the 60's and 70's, has large areas where daylight has little or no access. Moreover, the present lighting systems are inefficient, and it is believed that the large, dark areas adversely influence the well being of humans. Although this is still a somewhat controversial issue, the hospital authorities believe that more sunlight-like light could have positive biological effects. The ability to achieve higher lighting levels while reducing energy costs and cooling loads is another advantage.
The building housing the first prototype installation was erected in 1967. The original intentions of the architects were to create a soft and welcoming atmosphere in the entrance area by allowing natural light to enter through the glass facade. However, the facade didn't let in as much sunlight as had been hoped, and the inner parts of the entrance area were found to be very dark. Here, two parallel sulfur lamps with custom-built reflectors have been arranged in a way that directs the light upwards. A system of reflectors (not light pipes) in the ceiling distributes the light over the entrance area. Thus, the light is transmitted from the lamp unit via a primary reflector in the ceiling, as beams through the air, to a number of secondary reflectors that direct the light down towards the flow. The reflectors are clad with highly reflective films, but shaped so as to avoid any glare. Moreover, since these films have a microprismatic surface structure that "splits up" the beams, the risk of glare problems is further reduced. The fact that the reflectors "move" the light source far away from the eye of anyone that would happen to look into them helps to further eliminate glare problems.
Similar installations are planned for three more hospitals in southern Sweden. For instance, for the first time an underground radiotherapy clinic will be bathed in sunlight, albeit artificial.
