Science & Academic Articles
In this section, we compile scientific articles, technical publications, and expert contributions from around the world that focus on Heliobus® products, technologies, and daylighting solutions. The published technical articles highlight the importance of daylight for architecture, indoor environment quality, energy efficiency, well-being, and sustainable construction. At the same time, they document the international perception of and professional discourse surrounding Heliobus® solutions—ranging from technical applications and architectural integration to health and environmental considerations.
2026
Laboratory-based validation of glass-floor systems for zero-energy buildings
Scientific journal article / Open Access
The publication examines Glassfloor® Pure as a walkable glass flooring system for energy-efficient buildings. The test involved an 800 × 800 mm module with triple-pane insulated glass and a thermally broken stainless steel frame. Of particular relevance to architects is that the system was tested under laboratory conditions according to European testing methods for air permeability, watertightness, and thermal transmittance. The results demonstrate very high airtightness and a low U-value. For customers, the key message is: Glassfloor® Pure is not only a design-oriented daylighting solution but has also been technically and normatively documented.
2023
A Review of the Evolution of Daylighting Applications and Systems Over Time for Green Buildings
El-Saggan, M.E. · Rekabye, A. · Aissa, W.A. · Reda, A.M.
, Aswan University, Egypt, International Journal of Applied Energy Systems
This up-to-date and comprehensive overview from 2023 analyzes all 18 innovative Structure Core Daylighting Systems (SCDS) that are currently commercially available or have been tested on a large scale—ranging from Heliostat and TDGS to Parans and Echy. The authors provide detailed comparison tables for collectors, transport routes, and distribution systems across all technologies, along with efficiency and cost figures. Of particular relevance to architects: the health benefits of daylight are extensively documented—a 15% increase in productivity, a 14% improvement in academic performance, a 40% increase in retail sales, enhanced vitamin D production, and improved melatonin regulation. Energy savings of 10–40% in lighting are documented as realistic. The Heliobus system is documented as one of the few commercially available SCDS systems worldwide with actual installations, a quote available upon request, and a system efficiency of 20–30%. It is also clarified that Heliobus ranks among the more expensive but technically superior solutions—ideal for prestigious and sophisticated architectural projects. Heliobus is classified in its own system category with a photo, schematic diagram, and data table. The Swiss company has been recognized since 1999 as a pioneer in the commercially available, customized SCDS market.
2022
Test Report for the Construction Product – Glassfloor® Pure
Technical Test Report / Laboratory Report
The test report from the University of Žilina documents the standard-compliant testing of Glassfloor® Pure in climate chambers. The product was tested for air permeability, water tightness, and thermal insulation. The results show air permeability Class 4, water tightness Class 9A, and a vertically measured U-value of 0.60 W/(m²K). For architects and building owners, this provides strong technical assurance, particularly for roof, terrace, and floor glazing applications with high requirements for airtightness and energy efficiency.
2021
Effectiveness of Daylight Mirror Shafts as a Natural Daylighting System for Basements in Tropical Climates
Scientific article / Simulation study
The study examines the Heliobus® Spiegelschacht® / Mirror Shaft® principle for basements under tropical conditions. The authors explicitly describe the system as a daylighting solution introduced by Heliobus®. The simulation shows that reflective shaft surfaces can significantly increase illuminance compared to a shaft without mirrors; the study cites a 2.1-fold increase. At the same time, the study shows that the effect depends heavily on climate, room geometry, and design. For architects, the key takeaway is this: The Spiegelschacht® is an effective daylighting principle, but it must be sized specifically for each project and integrated into the architecture.
2019
Daylighting Systems for Buildings in High Latitudes
Obradovic, B. · Matusiak, B.S. · NTNU Trondheim, Norway
This review compares daylight transmission systems for high latitudes—that is, for climates with a low sun angle and frequently changing light conditions. Heliobus® is mentioned in connection with prismatic light tubes and daylight transmission in building cores. The publication is of interest to architects because it does not consider daylighting systems in isolation, but rather classifies them according to efficiency, integration, maintenance, cost, visual quality, and climatic suitability. The bottom line: daylighting systems can be valuable if they are selected to suit the location, building type, and use.
2019
International Work in the Field of Lighting Technology: Research Activity Report by Prof. Aizenberg
Aizenberg, Yu.B., Academician, VNIISI, Moscow; Russia
Svetotekhnika (Lighting Technology)
Professor Yuri Borisovich Aizenberg, one of the world’s most prominent lighting engineers of the 20th century and long-time chair of the CIE Technical Committee on Hollow Light Guides (TC3-30), provides a first-hand account of the development of Heliobus technology in this retrospective on 65 years of research. Together with Swiss engineer Rudolf Signer (Bühler-Scherler AG, St. Gallen), Aizenberg designed the concept and the first installation of the Heliobus system, which was implemented in a four-story school in St. Gallen and transports both daylight and artificial light through the same light pipe to all floors. The project received the Gold Medal at the International Environmental Protection Fair in Bern. This article is historically unique: It documents the scientific foundations (CIE Publications 164 and 173 on hollow light guides), the patent history, and the technology transfer from Russian basic research into a Swiss industrial product—with direct reference to Heliobus AG.
2017
Integration Challenges in Implementing Innovative Daylighting Strategies in Light Wells
Gholipour Gashniani, M. · Mehdizadeh Saradj, F. · Faizi, M.
, Iran University of Science and Technology, Tehran
This Iranian university study develops a systematic decision-making framework for the use of innovative daylighting systems in buildings with atriums—a design challenge that is becoming increasingly common in densely developed areas. The authors classify all major daylighting systems according to four integration criteria: light performance (quantity, quality, uniformity), cost-effectiveness (investment, operating, and maintenance costs), structural compatibility (structure, building services, cityscape), and social acceptance. Indispensable for architects: The decision-making model provides direct assistance in selecting a system for specific project situations. The Heliobus mirror system is classified as a “Redirecting Collector” and evaluated according to all four criteria—with the conclusion that it performs particularly well when the sun is low in the sky (typical for north-facing atriums and basements in Central Europe). The study also emphasizes that a focus on efficiency alone is insufficient—building integration and user acceptance are equally crucial.
2017
Improving Solar Exposure Conditions in Urban Areas Using Light Guide
Gritsiyenko, D. · Kasyanov, V., Moscow State University of Civil Engineering, Russia
MATEC Web of Conferences 106, 01015 (2017) · DOI: 10.1051/matecconf/201710601015 · SPbWOSCE-2016 · EDP Sciences Open Access
In this open-access article, researchers from Moscow State University of Civil Engineering analyze the history and classification of light-guiding systems since the 19th century and, for the first time, develop a concept for improving sunlight exposure in urban buildings with limited sunlight using light guides. The historical overview is revealing: as early as 1850, Paul Emile Chappuis patented reflectors for redirecting daylight into basement and ground-floor rooms—the direct precursor to today’s Heliobus light well. The study shows that light pipes can be used in building renovations to supply even north-facing, shaded facades with sunlight from south-facing surfaces—a novel urban application. For architects: The paper opens up systematic considerations regarding the use of passive light-guiding systems in the renovation of existing buildings under the conditions of European inner-city densification. The classification of light-guiding systems (HTL vs. fiber optics) is precise and relevant to planning.
2017
Integration Challenges in Implementing Innovative Daylighting Strategies in Light Wells
Gholipour Gashniani, M. · Mehdizadeh Saradj, F. · Faizi, M., Iran University of Science and Technology, Tehran
Journal of Applied Engineering Sciences
This Iranian university study develops a systematic decision-making framework for the use of innovative daylighting systems in buildings with atriums—a design challenge that is becoming increasingly common in densely developed areas. The authors classify all major daylighting systems according to four integration criteria: light performance (quantity, quality, uniformity), cost-effectiveness (investment, operating, and maintenance costs), structural compatibility (structure, building services, cityscape), and social acceptance. Indispensable for architects: The decision-making model provides direct assistance in selecting a system for specific project situations. The Heliobus mirror system is classified as a “Redirecting Collector” and evaluated according to all four criteria—with the conclusion that it performs particularly well when the sun is low in the sky (typical for north-facing atriums and basements in Central Europe). The study also emphasizes that a focus on efficiency alone is insufficient—building integration and user acceptance are equally crucial. The Heliobus collector is listed as a separate system category in the global classification of innovative daylighting systems and evaluated according to all relevant integration criteria.
2014
Classification of Indoor Daylight Enhancement Systems
Nair, M.G. · Ramamurthy, K. · Ganesan, A.R. · IIT Madras, India
This publication classifies innovative daylighting systems into categories, including light-guiding systems, light-transport systems, hybrid systems, and integrated systems. Heliobus® is cited as a reference in an early technical publication on the hollow light guide system. This resource is helpful for architects because it compares daylighting systems based on integration complexity, maintenance, efficiency, light output, availability, and climatic suitability. The bottom line: Heliobus® is part of an internationally recognized family of systems designed to improve daylighting in deep or hard-to-illuminate interior spaces.
2011
Hybrid Lighting Systems: A Feasibility Study for Europe
Mayhoub, M.S. · Carter, D.J., University of Liverpool, UK
Peer-reviewed conference paper · University of Liverpool, School of Architecture
This quantitative feasibility study by the University of Liverpool evaluates hybrid daylight/artificial lighting systems for office buildings at 12 European locations—from Oslo to Athens, from Bordeaux to Moscow. Four different system types (TDGS, HSL, Parans, SCIS) are simulated in various building configurations (single- and multi-story, deep and narrow buildings). Key finding for building owners and designers: Depending on the location and system, between 28% (Oslo, TDGS) and 85% (Crete, SCIS) of artificial lighting needs can be replaced by daylight. Even in Central Europe (Switzerland, Germany, Austria), savings of 40–60% are realistic. The study also shows that systems with large collector areas (such as Heliobus installations) represent the most effective solution, particularly in existing buildings and on basement levels. For architects, this is an indispensable reference document for justifying daylight investments to building owners on economic grounds.
2010
Towards Hybrid Lighting Systems: A Review
Mayhoub, M.S. · Carter, D.J. · University of Liverpool
The article examines hybrid light-guiding systems in which daylight and artificial light are brought into and distributed throughout buildings together. Heliobus® is cited as a reference system in the context of hollow light pipes and hybrid lighting systems. This resource is valuable for architects because it identifies the design challenges of such systems: daylight yield, investment costs, operation, user acceptance, geographical suitability, and integration into the building structure. The bottom line: Heliobus® is recognized as an international industry standard in the field of hybrid daylight and light-guiding systems, although planning must be carried out early on and in a holistic manner.
2010
Daylight Transportation: A Green Lighting Technology to Save Energy
Institution of Engineers India, Architecture
The article compares various daylighting systems, such as mirrored light tubes, optical fibers, prismatic light pipes, lens systems, and acrylic rods. Heliobus® is described as a hollow-prism light pipe system that was installed at the Boppartshof School in St. Gallen to illuminate the core of a four-story building. The article describes the heliostat, transition element, integrated artificial lighting component, vertical prismatic light pipe, coupler, and diffuser unit. For architects, this resource is valuable because it cites Heliobus® as an example of multi-story daylighting in building cores.
2010
Towards Hybrid Lighting Systems: A Review
Mayhoub, M.S. · Carter, D.J., University of Liverpool, UK
, Lighting Research & Technology
This influential review article, published in one of the leading journals in lighting technology, analyzes all hybrid lighting systems (combining daylight and artificial light in a single integrated unit) implemented up to 2010. The authors from the University of Liverpool examine light output, costs, user acceptance, building integration, and design methods for systems such as HSL, Parans, SCIS, and Heliobus. Key message for designers: Hybrid systems significantly outperform pure daylight tubes in terms of light quantity and quality; those who want to create “daylit spaces” need integrated solutions. The study demonstrates, based on user surveys, that office buildings with daylight guidance achieve significantly higher satisfaction levels. The Heliobus system is documented with concrete measurement values: Under overcast skies (10,000 lux outside), 420 lux was measured directly at the outlet indoors, dropping to 30 lux at a distance of 3 meters. The study also discusses fire safety requirements for light-guiding systems spanning multiple floors—directly relevant to current standards.
2009
Lighting Systems in Smart, Energy-Efficient Buildings: A State-of-the-Art Review
Barbara Matusiak, NTNU / SINTEF, Norway
SINTEF Report STF22 A04504 · Norwegian Research Council
This state-of-the-art report by the Norwegian research center SINTEF and NTNU examines which lighting systems are crucial for the energy-efficient buildings of the future. Key message: Hybrid lighting systems that intelligently combine daylight and artificial light are the key to reducing energy consumption in buildings without compromising user comfort. The document contains a comprehensive classification of all daylight control systems available at the time and explicitly positions Heliobus as one of the few real-world, fully implemented examples of an integrated daylight/artificial light concept in a multi-story school building in St. Gallen. Particularly valuable for architects: The report analyzes which stakeholders (architects, engineers, investors, users) have what expectations of daylighting systems, and shows that users prioritize well-being, visual quality, and flexibility above all else—values that Heliobus products fulfill to a particularly high degree. Energy savings of 50–90% in artificial lighting are demonstrated as realistic.
2002
Daylighting via Optical Fiber
Master's thesis / academic thesis
This master’s thesis from Luleå University of Technology analyzes various daylighting systems. The description of the project at Potsdamer Platz in Berlin is particularly relevant to Heliobus®: there, light tubes connected to heliostats link the outdoor space with the underground station. The thesis emphasizes that the light tubes not only provide lighting but also create an architectural connection between the surface and the underground. Furthermore, the Heliobus® system is described in general terms, including the heliostat, transition element, light guide, and couplers. The key takeaway for architects: Heliobus® daylighting technology can not only transport light but also create spatial orientation and architectural identity.
1997
Principal New Hollow Light Guide “Heliobus” for Daylighting and Artificial Lighting in the Central Areas of Multi-Story Buildings
Conference paper / scholarly historical publication
This early technical publication is a key historical reference on the Heliobus® light pipe system. It is cited in several subsequent scientific papers and reviews. While it is less suitable for the website as modern product documentation, it serves as strong evidence that Heliobus® has been recognized in international daylight research and building technology since the 1990s. The bottom line: Heliobus® was an early part of the scientific discussion on illuminating building cores and multi-story interior spaces with natural light.