On the integration of Non-Image-Forming effects of light on venetian blinds and electric lighting control

Light induces important “Non-Image-Forming” (NIF) effects on human physiology and behavior, such as improvement of alertness, cognitive performance and mood. Considering these effects in office lighting can improve well-being and productivity of the occupants. This study introduces and evaluates NIF effects of light on humans within a Building Automation System of an office environment. Real-time luminance mapping is assessed by novel HDR vision sensors; the monitored data is used for a smart user-centric controller of the indoor electric lighting and sun shadings. A preliminary evaluation of this advanced controller was carried out during one week in a single-occupied office in the LESO solar experimental building at the Swiss Federal Institute of Technology (EPFL) in Lausanne, Switzerland. The system demonstrated to have sound capabilities in satisfying visual comfort conditions and well-being for the office's occupant.

Toward an Integrated Platform for Energy Efficient Lighting Control of Non-Residential Buildings

Laurent Deschamps, Ali Motamed, Jean-Louis Scartezzini

Net energy import of Switzerland corresponds to about 13 BCHF (petroleum, uranium, etc.) each year. According to the energy perspective 2035 defined by Swiss Federal Office Energy, the energy import should be reduced to 7.3 BCHF. Meeting the goals defined by this perspective can be envisaged by mitigating the energy demand of buildings since the built environment consumes 40% of the total primary energy. In Switzerland; 20 % of the buildings’ energy consumption is moreover related to electric lighting. Therein, integrated building automation technologies, such as automatic regulation of sun shadings and electric lighting can play an important role in reducing lighting energy demand while maintaining user comfort. For this purpose, a rapid, reliable, accurate evaluation of the lighting conditions in a building is essential. In this paper, a control platform installed in two offices of the LESO experimental building on the EPFL campus in Lausanne, Switzerland is presented. This data acquisition and actuation platform hosts two motorized sun shadings per office, a dimmable lighting system, a presence detector, energy meters, ceiling mounted luminance-meters and two novel High Dynamic Range (HDR) vision sensors. A sample controller is implemented in the platform to evaluate its robustness and performance. This platform is currently ready for integrating novel controllers for testing several energy efficient control scenarios/algorithms.

vdf Hochschulverlag AG ETH Zurich2016

Energetic, Visual and Non-Visual Aspects of Office Lighting

Friedrich Linhart

Light has important visual and non-visual effects on humans and high-quality light should therefore be supplied inside buildings in sufficient quantities. On the other hand, artificial lighting is responsible for a large part of an office building's electricity needs. It is thus important to take into account at the same time visual comfort, non-visual effects of light and energy-efficiency when designing lighting systems for office buildings. The general objective of this doctoral thesis was to combine knowledge from several scientific fields (e.g. daylighting technology, artificial lighting technology, lighting simulation and chronobiology) to discuss how sustainable lighting solutions (i.e. lighting solutions that are optimized in terms of energy-efficiency, visual comfort and performance as well as non-visual aspects of lighting) can be achieved in office rooms. A research strategy that used a test office room equipped with an Anidolic Daylighting System (ADS) as a starting point has been followed. This ADS was shown to be well-accepted by office occupants and to be able to supply sufficient daylight flux during large parts of most working days. Based on this ADS, a highly energy-efficient electric lighting system for complementary artificial lighting was developed and tested in a visual comfort and performance study with human subjects. In addition to that, the chronobiological properties of the test office room were assessed. It was shown that the ADS-equipped room performs extremely well under daylighting conditions in terms of non-visual aspects of office lighting. For the rare times when this is not the case, a back-up system for chronobiological lighting based on blue Light Emitting Diodes was developed. In order to get a deeper insight into chronobiological aspects of office lighting, a first applied chronobiological study at the Solar Energy and Building Physics Laboratory was initiated. Furthermore, possibilities to apply the concepts developed during this doctoral thesis to other types of buildings and other geographic regions were discussed. In conclusion, this doctoral thesis successfully demonstrated that it is possible to achieve sustainable lighting scenarios that are optimized in terms of energy-efficiency, visual comfort and performance as well as non-visual aspects by combining day- and electric lighting technologies in an appropriate way.

EPFL2010

Self-commissioning glare-based control system for integrated venetian blind and electric lighting

Laurent Deschamps, Ali Motamed, Jean-Louis Scartezzini

Rule-based control logics have proven to be efficient for automation of shading and lighting systems. However, successful commissioning of these systems for multiple stores non-residential buildings, regardless of the control logic, requires time-consuming programing and fine-tuning of numerous parameters. In this article, a control approach is suggested to overcome the limitations of the rule-based control systems: i) necessity for extensive information on the office room, ii) costly adaptation of control parameters to a new environment, and iii) no feedback to the control system in the case of mal-function. A novel self-commissioning approach is proposed: a set of open-loop geometry-based rules are enhanced with a supervised learning module for fine-tuning seven tunable parameters. This approach was validated through an in-situ experiment for 22 days in a daylight testbed equipped with internal venetian blinds, dimmable electric lighting system, a miniaturized accurate High Dynamic Range vision sensor to evaluate Daylight Glare Probability (DGP), horizontal illuminance meters and a pyranometer. The goal was to command the shading and electric lighting system to keep the DGP and horizontal illuminance in a predefined visual comfort zone. A novel visualization method is proposed to demonstrate the performance of the automatic system in leading the indoor environment to the visual comfort zone. After 11 days, the learning module reached the convergence state. Afterwards, the controller was capable of successfully confining the indoor illumination conditions to the visual comfort zone for 96% of the working hours while actuating the shading system efficiently; on average 2.54 times a day.

2020

Energetic, Visual and Non-Visual Aspects of Office Lighting

Friedrich Linhart

EPFL2010