Skip to main content
European Commission logo print header

An Innovative Solar Lighting System to replace artificial lighting in all types of indoor spaces with free and healthy sunlight.

Article Category

Article available in the following languages:

New system collects and channels natural sunlight to buildings’ interiors

People need access to natural sunlight every day, not only when they are on holiday. This realisation is spreading among experts and academia to policy makers and citizens, who are embracing the change to a healthier living and working environment.

Industrial Technologies icon Industrial Technologies
Energy icon Energy

Natural sunlight helps boost vitamin D, ward off seasonal depression, improve sleep and avoid the risks associated with fluorescent lighting. Fortunately, we are now on the verge of a lighting revolution, returning to natural sunlight and abandoning unhealthy and wasteful artificial lighting during daylight hours. The EU-funded SOLIS project addressed this challenge by developing an innovative, affordable and cost-effective sunlight collection and channelling system, SOLIS (SOlar LIghting System), which uses healthy natural sunlight for interior daytime lighting. Researchers developed a system based on ideal optical efficiency, and lighting uniformity, without resorting to delicate and costly tracking technologies. “SOLIS collects and transmits full-spectrum solar light indoors with unparalleled performance, providing commercial and residential buildings with a cost-effective Human Centric Lighting solution,” says Ofer Becker, project coordinator and Chief Technical Officer of Solight Ltd.

Durable and cost-effective

Work began with a delicate and expensive working prototype, which was difficult to assemble. Building on their combined experience and extensive field testing, researchers improved the design, focusing on simplification and durability. The final system comprises a highly innovative optimised static collector, a light transporting waveguide, and a hybrid light dispersing end unit. The combination of these three modules produces a robust and maintenance-free system capable of delivering up to 40 000 lumen per square metre of the collector area. “Compared to the most direct competition, SOLIS doubles the sunlight harvested from the outside of the buildings (on rooftops or southern walls), minimising the expensive and unhealthy indoor artificial light use,” Becker explains. In addition, SOLIS employs a range of patented optical improvements, which accurately map the daily and annual positions of the sun, so that at any given moment, the most suitable parts of the system are actively channeling natural sunlight indoors. According to Becker: “These optimisations enable us to deliver from 8.00 in the morning till 16.00 in the afternoon full spectrum light with no heat or UV, making SOLIS a healthy and safe natural sunlight source.”

Different systems for different users

The project targeted three different markets. The first system is a single SOLIS Industrial unit that can light up to 60 square metres and is designed for large buildings such as schools, factories, hospitals, retail centres, and retirement homes. The second, SOLIS Versa, is aimed at the residential sector, significantly brightening any home to make it healthier and more pleasant to live in. Lastly, the DIY SOLIS Mini can illuminate basements through egress windows, and is suitable for energy conscious off-grid small homes. SOLIS delivers unparalleled performance featuring high yields and continually lowered costs, making it highly applicable to a large number of sectors within the market. “It will benefit architects, lighting designers, urban planners, and home owners, by providing freely available, and healthy, natural sunlight to living and working spaces, enabling up to 40 % saving in the electricity costs of big buildings like office blocks, 18 % productivity increase, 26 % faster learning in schools, and 41 % shorter recovery in hospitals,” Becker concludes.


SOLIS, natural sunlight, Human Centric Lighting, optical, module, optimised static collector, SOLIS Industrial unit, SOLIS Versa, DIY SOLIS Mini