Transporting natural light to dark corners

by: Mirjam Visser, 2011-02-01 10:37:29 UTC
Sustainability Aspects: bringing sun light in dark corners by using computer steered reflectors

The system

Indoor lighting systems powered by light not energy. The Parans SP2 panels are placed outside a building to capture sunlight, which is transported via a system of movable reflectors to indoor light fixtures consisting of flexible fiber optics. A bit like the old Arabian solutions to mirror light through funnels.
A microcumputer automatically moves the reflectors to guarantee a maximum amount of light during the day. In such a way also buildings with few or windows can have daylight inside.

Solar Tracking
A sun sensor, based on a PSD chip, has been developed and assures increased accuracy in detection and tracking of the sun in a large variety of weather conditions. The software combines input from the sensors with historical data of the solar path from each day that the panel has been installed.This allows for alignment of the lenses towards the sun even on cloudy days, so that sunlight can be harvested as soon as the sky is clear.

Function Description
The sunlight output from Parans SP2.1 depends on the sunlight conditions and the length of the fiber optic cables. The light transport is immediate, it cannot be stored and is not transformed. If a cloud passes by for example, the same shadow will be cast indoors and if the sunlight is tinted red in the evening so will the light output. For light to be able to flow through an optical fiber, it must enter from an angle which lies within the fiber’s acceptance angle. In practise, this means that only the parallell light rays of direct sunlight can be efficiently collected.The light output on cloudy days is therefore little or none depending on the thickiness of the clouds.

At direct incadent sunlight at 100 000 lux, the sunlight output, or luminousity, from Parans SP2.1 is 3000 +/- 300 lumens. The transmission in the optical cables is 95,5% per meter, which means for example that 63% luminousity remains after 10 m.

WWF and GlobalFOCUS awarded Parans Climate Solver for being one of Sweden’s 12 most important climate innovators.

Designer: Bengt Steneby
Manufacturer: Parans Solar lighting
Category: solar lighting


The system
by parans

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