Daylight in Self Sufficient Housing Units

Detailed Simulations of Lighting Conditions in Office Rooms Lit by Daylight and Artificial Light

Daylighting Systems for Core Illumination of Offices in Scandinavian Climates

The Impact of Light Including Non-Image Forming Effects on Visual Comfort

By Apiparn Borisuit, EPFL Solar Energy and Building Physics Laboratory, École Polytechnique Fédérale de Lausanne EPFL, Switzerland

Visual comfort at workplaces has often been considered in terms of discomfort glare, luminance distribution and task visibility. Besides visual effects, the lighting environment has also impact on human physiology and behaviour. These effects of light are transmitted via a novel class of photoreceptors in the mammalian retina, which was discovered only a decade ago. Since then, it has become evident that light also plays an important role in regulating Non‐Image Forming (NIF) functions such as circadian rhythms, alertness, well‐being and mood. In lighting design it is accordingly necessary to take into account not only luminous intensity, but also light’s spectral composition, since the novel class of photoreceptors is more maximally sensitive to different luminous wavelengths than the classical photoreceptors (e.g. rods and cones).

The main focus of this doctoral thesis is on visual comfort assessment at workplaces. It was hypothesized that the impact of light on visual comfort comprises not only luminance distribution and/or luminous intensity, but also other qualitative aspects of the lighting environment. Office lighting influences building occupants in terms of visual task performance, alertness, health and well‐being. The aim of this thesis was to assess the impact of office lighting on visual comfort including NIF effects.

Firstly, in order to monitor the luminance distribution within a scene, a new photometric device based on a high dynamic range logarithmic visual sensor (IcyCAMTM) was set up. After calibrations and validations, the photometric device was used to assess luminance distribution of office spaces in a very efficient way. Secondly, two experimental studies were performed with human subjects, aiming to test the acute effects of light on visual comfort variables, subjective alertness, mood and well‐being. Lastly, the novel device was also used during one of the studies to monitor the impacts of luminous distribution over time and under various lighting conditions.

The novel photometric device enables to assess luminous distribution also in circadian metrics with respect to NIF effects of light. The results from the two studies showed the effects of office lighting including different sky conditions and time‐of‐day changes on visual comfort and NIF functions. Inter‐individual differences, as assessed in extreme chronotypes, also had an influence on visual comfort. Interestingly, luminance distribution was not only found to impact on visual comfort but also on subjective alertness, mood and well‐being. To conclude, the results obtained with the new device provide a more comprehensive scientific framework and practical basis for indoor lighting design at workplaces.

Apiparn Borisuit defended her PhD thesis in December 2013. The entire dissertation can be downloaded at http://infoscience.epfl.ch/record/190815

How Office Occupants Experience Intelligent (Day)lighting Control Systems

Optimization of Daylight in Buildings in Prevailing Clear Sky Conditions

The Impact of Light and Color at the Perceived Quality of Sustainable Dwelling Architecture

Influence of Presentation Modes on Visual Perceptions of Daylit Spaces

By Coralie Cauwerts, Université Catholique de Louvain (UCL), Faculty of Architecture, Architectural Engineering and Urban Planning (LOCI), Architecture et Climat, Louvain-la-Neuve, Belgium

Virtual renderings are increasingly used in the architectural design process and in lighting quality research to assess the visual appearance of indoor environments. Thanks to imaging technologies continuously in development to improve the “realism” of these images, pictures can nowadays be presented in various ways. Regrettably, to date, few studies assert that such images replicate the visual appearance perceived in actual daylit environments.

The present research investigated the perceptual equivalence between actual daylit environments and images. Two types of images – photographs and virtual renderings – were studied as well as four modes of presentation – QuickTime virtual reality (QTVR) panoramas, 2D display, 3D display, and high dynamic range (HDR) display.

ight groups of 40 students viewed four daylit corridors and filled in a questionnaire about the appearance of lighting and space elaborated for the study. The corridors were presented in several ways: a first group of participants visited the actual rooms while the other groups visualized, in a lab context, their reproduction in sketches, photographs or virtual renderings.

This research provides some proofs that images can reasonably be used as a surrogate for the real world when studying the appearance of lighting (characterized by the perceived brightness, coloration, contrast, distribution, directivity and glare). On the other hand, the study suggests that images poorly reproduce the appearance of space (pleasantness and enclosedness were studied). As a result of the research, we determined precisely the media to use for studying each dimension characterizing the appearance of lighting and space.

Coralie Cauwerts graduated from the Louvain School of Engineering (EPL) at the Université catholique de Louvain (UCL) with a Master in Architecture and Engineering in 2007. She conducted her thesis between 2009 and 2013 as a research fellow of the Fonds de la Recherche Scientifique (FNRS) and she successfully defended her PhD thesis in November 2013.

The entire dissertation can be downloaded at http://hdl.handle.net/2078.1/135934.

Natural Light, Lighting Qualities for the Design of Future Spaces

A Method for Holistic Evaluation of Sustainable Buildings of the Future

Exploiting Daylight in Industrial and Commercial Buildings

Health Consequences of Light Environment in Indoor Work and Night Work

Daylight and View

By Hester Hellinga, Delft University of Technology, Faculty of Architecture and the Built Environment, Delft, Netherlands

A window doesn’t only allow daylight to come inside, but also offers a view of the outside environment. View has a much bigger influence on the overall appearance of indoor spaces than people are generally aware of. Glare by daylight, for instance, is experienced as less disturbing when the outside view is of a high quality.

Aim of my PhD research was to develop a method for the analysis of the daylight and view quality of windows, the D&V analysis method. Initially, office workers in eight different buildings in the Netherlands were questioned on the quality of their workplace concerning the office, the lighting and the view. Subsequently, the D&V analysis method was developed based on scientific literature and the results of the questionnaire study.

The analysis method includes a rating system for view quality. It grants points for several aspects of the view. If you’re looking at nature, it’s plus four points, if your view is human-built there are no points to start with. This basis is refined by points for the amount of visual layers (depth of view), presence of water, vegetation, the amount of diversity etcetera.

In another set-up was studied how the appreciation of the daylight access and the outside view varied with different window size, shape and position. Participants in this study were asked to look outside through a miniaturised (1:5) office room. By varying the façade of the scale model, the influence of different windows and views was studied on the visual quality of the office room.

This latter study made clear that people wanted a window at least a quarter the size of the wall, but not a fully glass wall. The shape of the window was of secondary importance, but panorama was favoured above portrait. The sky component (what part of the view is sky) was a pretty good indicator for the amount of incident daylight.

I hope that my study will contribute in putting the view on the architect’s agenda. A proper placement of a building on the lot, respecting lines of sight and making the best of adjacent green can – for the same price – improve people’s appreciation of their views and thus of the spaces they occupy.

The dissertation can be downloaded from the website of the university library: http://repository.tudelft.nl/view/ir/uuid:2daeb534-9572-4c85-bf8f-308f3f6825fd/

Evaluation of Climate-based Daylight Metrics in Real Spaces, in Scale Model Spaces and with Simulation Tools

Integrated Energy Design in Masterplanning

by Jakob Strømann-Andersen, Henning Larsen Architects and Technical University of Denmark, Denmark

This PhD thesis considers urban structure and buildings in an energy correlation and use the knowledge to design energy- and comfort-optimized cities and buildings. The parameters are: the structure of nature, the city and the landscape, both in terms of geometry and interrelationships and in terms of opportunities and limitations with regard to light, shade, sun and wind.

The aim is threefold: (1) to unfold the link between building energy use and urban density, typology and fabric; (2) to analyse how technical scientific knowledge can be integrated in early urban planning and design decisions (IED); and (3) to show the architect’s responsibility and opportunities to rethink their architectural role based on new goals and knowledge.

The research results show an impact from urban form on building energy consumption which is much greater than previously thought, more precisely described, and more dynamic in character as daylight is taken into account. Furthermore the results suggest that there are limits to urban densification (200–300%) as an energy optimization strategy. The solar energy and daylight potential should be considered, and indeed protected, as a common resource in urban design.

The most important observation for qualitative design research is that the first step to improving energy performance must be taken with the architect’s first sketch on paper. It is here that the framework and preconditions for the city and the building’s performance will be set. Argued this way, optimization of the special properties of urban density, typology and fabric takes priority over the optimization of technical service systems. This means that in the design process the architect’s responsibilities outweigh those of the engineers. The research is reported in the main body of this thesis and in the papers for scientific journals.

Jakob Strømann-Andersen, Henning Larsen Architects, successfully defended his PhD thesis titled ’Integrated Energy Design in Masterplanning’ at the Technical University of Denmark. The research is based on a close collaboration between the Technical University and Henning Larsen Architects – with support from Realdania.

The PhD Thesis can be downloaded at http://www.byg.dtu.dk/english/~/media/Institutter/Byg/publikationer/PhD/byg-r254.ashx

Thermal and Visual Comfort from An Occupant Centered Perspective: Emphasis on the Influence of Socio-cultural Parameters

Human Sensitivity to Different Lighting Conditions

Design Parameters of Pleasurable Light Atmosphere

by Lone Stidsen, Aalborg University, Denmark

At the moment, the future of hospital design is a subject of interest and thereby also a subject of discussion. It is a fact that new hospitals have an increased focus on user perspectives and an interest for improving the physical environment in such a way it supports the user needs and preferences and thereby the experience of an admission to the hospital. Recent literature such as “Hospitals of the senses” and “Healing Architecture” presents research and design solutions focused on senses and experience of the design. The Danish Regions ask for Evidence Based Design to future prove the hospitals by research base the design of the buildings. The present PhD project expands the existing knowledge of lighting research by focussing on the experienced light atmosphere. The project uses multi strategies of methodology based on a flexible design to elaborate on the socio-cultural aspect of light and the sensory impact of light. To frame the work, the “Model of Light Atmosphere” is created and improved throughout the study, first as an abstract model and then it is exposed for detailed study. The detailed study first of all creates a theoretical and visual context. Then explorative studies seek to investigate unknown or tacit knowledge on how light is used in a Danish context, preferences for light in different situations and investigating the hospital ward as frame for a lighting concept. The concept is installed in a hospital ward at Odense University Hospital as a “real world” study and evaluated by the patients in the ward.

The project is based on the Danish Regulation for light in hospitals (DS703), which is a supplement to the regulation of artificial lighting in workplaces (DS700). The kick-off to the project was reading the DS703, second paragraph, chapter 2 about general requirements for lighting.

In general, measurable parameters such as the amount of Lux, the composition of CRI and degree of Kelvin is described precisely in a way so the designer can handle the requirements. But what does it mean to create a “home-like” and “pleasant or appealing” light in this context? Does the composition of CRI and degree of Kelvin tell it all? Is it enough information to provide an illumination, which the patient can experience as homely and pleasant?

This project seeks to highlight the design process of lighting a hospital ward and articulate visual as well as written what a homely and pleasant light atmosphere could be in a Danish context. Therefore, the study investigates the socio-cultural understanding and the geographical impact of the understanding of light atmosphere. “Model of Light Atmosphere” Ill: 12 describes four key aspects of light atmosphere and displays what is important when a light atmosphere is qualified. The four key aspects are: “Light”, “Space”, “Users” and “Time”.

The “Light” aspect describes, as shown in the figure below, the character of the light, light information and light effect i.e. function, aesthetics or symbolism. The “Space” aspect looks into the dimension of the space, geographical orientation, interior design, composition of the space, materials, surfaces and objects. The parameter “Time” elaborates on the time one is present in the space, the season and time of day. The “Users” aspect is split up into categories such as characteristics exploring the user group’s preferences and needs. The user group has quite diverse needs and preferences, while the staff needs task lighting and the patient a space experienced as homely and pleasant.

“Model of Light Atmosphere”

Categories such as “pleasure” and “activities” are also a part of the user aspect. The space is divided into subcategories as ”location of the space” and “geographical orientation”. The interior design, surface and spatial composition of the space are also parameters of importance.

The model “Light Atmosphere” is the focal point of the project through iterative process and also developed through the study. First the model frames the study and later serves as a design tool for creating light atmosphere in hospital wards.

The project is performed through four cycles of iterations. The first cycle describes the “State of the art” in the research field “Atmosphere”. Here the study find its theoretical foundation based on Gernot Böhmes’ concept of atmosphere. It also finds its visual understanding by studying the architects’ way to design atmosphere. The second cycle explores the users’ preferences and trends of light atmosphere in four exploratory studies. First presented is a study of light preferences in Danish homes. Then, the trends of light atmosphere in Denmark are investigated and light zones at the hospital ward defined in order to optimize the illumination. Lastly, an observation of ward atmosphere is presented. The third cycle of iteration is an experimental study testing a lighting concept developed and grounded in the knowledge gained through the first and second cycle. The fourth cycle evaluates the effect of the light atmosphere at the ward. Here the patients are admitted to two similar wards not including the artificial illumination. The evaluation uses Semantic Environmental Description developed by environmental psychiatrist Rikard Küller, in order to evaluate the light atmosphere.

The thesis can be downloaded from http://riverpublishers.com/book_details.php?book_id=246

Further information at www.lostdesign.dk

Light Space – the Spatial Potentials of the Facade

Modeling View Direction – Towards the Objectification of Discomfort Glare

by Mandana Sarey Khanie, Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland

In this work the fields of architecture, building technology and psychophysics come together in search for objective relationships between perceived comfort, occupant response patterns and lighting conditions in office spaces. Depending on the occupants’ seating position and view direction, light distribution in the field-of-view (FOV) can range from interesting highlights to visually discomforting situations, commonly known as discomfort glare. There are several discomfort glare metrics that can be used at the design phase to predict discomfort glare risks. A major limitation, shared by all known glare metrics, is that the dependencies of glare on view-direction are ignored and the calculated glare is only valid for a specific view-direction and seating position. This study seeks to eliminate this limitation through a deeper understanding of the dynamics of view-direction as a result of light distribution across the FOV.

The methodological novelty in this study relies on experiments in which the eye movements of human participants are measured in a parameterized office-like environment. Concretely this implies using an eye-tracking head-mount camera while the participants are exposed to different light conditions. Photometric quantities, which are relevant to visual comfort, will be recorded continuously during each experiment trial. The hypothesis is that there are clear view-direction distributions patterns under different lighting conditions which will ultimately have a significant effect on evaluations of discomfort glare and lead to better integration of glare-free daylight solutions in buildings design. This endeavor will ultimately foster a factor in visual comfort prediction models, which will enable the accounting for one’s actual position and view direction in space in a work environment.

Integrated Energy Design of the Building Envelope

Integrated Energy Design of Larger Buildings

Nordic Light

Selection of Glazing and Shading Devices for Office Buildings

Sustainability – Energy Optimization – Daylight and Solar Gains

This thesis discusses how energy optimization focused on daylight and solar gains may be qualified as an architectural design method, which does not just increase the energy efficiency of the built environment, but may potentially increase its overall qualities by offering new insights into the complex interrelationships between urban and building design, environmental performance, human needs and behaviour, technology and energy use.

The main hypothesis is that a hierarchy of scales related to energy optimization and environmental performance may be used to guide and support architectural design decisions in the earliest design stages. The hypothesis is examined through literature studies, empirical observations, interviews with practitioners, a series of simulation studies focused on energy optimization, solar gains and daylight, and a final case study applying derived design principles in an architectural design competition.

The aims are:

1. To situate energy optimization and environmental performance as qualitative architectural design issues which should also be understood in quantitative terms, by discussing these in a wider cultural and social context of sustainability.
2. To investigate the impact of basic urban and building design decisions on energy use and environmental performance in Northern Europe, using the central city districts of Copenhagen as references.
3. To combine the insights gained into a theoretical framework, relating the various aspects of energy optimization focused on daylight and solar gains into a coherent methodology.

The thesis demonstrates that not just one, but several functional and cultural hierarchies of scales can be found from practical and theoretical studies and combined into a coherent theoretical framework. It confirms that the most basic architectural design decisions – urban density and pattern, building form and material choice, window to wall ratio, colour and insulation properties of facades, have great impacts on energy use and environmental performance, which is described with more detail and greater precision than previous studies, by adding climate based daylight analysis to thermal and energy simulations.

Design issues related to urban density receives particular attention as the bottom level of a hierarchy of scales, in addition to addressing the trend of increased urbanization and urban densification which is seen internationally as well as in Denmark. It is found that an optimal range of urban densities can be defined balancing building energy efficiency with access to sun and daylight depending on regional climate. In Northern Europe this density can be described as plot ratios between 100 – 300%. But great environmental performance differences among building typologies within this range indicates that there is plenty of design opportunity to improve environmental performance of buildings by working with urban design, building form and orientation and the geometry and properties of the building skin.

It is argued that it is more important to see energy optimization as a creative opportunity to create better, diverse and stimulating environments using urban and building design as the key instruments, rather than focusing on narrow optimization of technical subsystems. The results demonstrate that daylight and solar access is more dependent on urban scale design decisions than energy use, and should therefore be considered primary design objectives in the very beginning of the design process in the context of Northern Europe.

The thesis can be downloaded at http://orbit.dtu.dk/en/publications/sustainability–energy-optimization–daylight-and-solar-gains(8f401bbe-2f4d-4602-81f3-a7b85a106c03).html

Spectral Modulation of Melanopsin Response – Role of Melanopsin Bistability in Pupillary Light Reflex

By Petteri Teikari, Université Claude Bernard and Stem Cell and Brain Research Institute, INSERM U846, France

In addition to the canonical photoreceptors, rods and cones, a novel melanopsin-expressing retinal ganglion cell (mRGC) was recently discovered. The novel photopigment melanopsin in the human retina has been shown to express invertebrate-like bistable properties both in vitro and in vivo. In bistable photopigment systems, light elicits photosensory responses and drives photoregeneration of the chromophore to restore photic responsiveness. These studies have shown that prior light exposure can modulate the amplitude of subsequent photic responses of melanopsin.

In this thesis, the putative bistability of melanopin in humans is examined. The bistability was studied using 1) pupillary light reflex (PLR) as a tool, 2) developing a method for quantifying the effects of lens density for melanopsin-mediated photoreception, and 3) providing a quantitative mathematical framework for modeling bistable pigment systems and non-image forming (NIF) visual system.

Exploiting the bistable properties of melanopsin could allow for optimization of spectral light distribution in experimental, industrial, domestic and clinical phototherapy applications by appropriate use of the photoregenerative effects of long wavelength light.

Further information at http://www.petteri-teikari.com/

Algorithmic Optimazation of Visual Comfort and View Out in Office

Energy Efficiency in Lighting – Daylighting Design for Energy Saving and Visual Comfort Purpose

Parametri i Praksis – Generative Performance i Arkitektur

by Tore Banke, The Royal Danish Academy of Fine Arts, School of Architecture, Design and Conservation, Denmark

This PhD project examines the development of parametric sketch tools that integrate multidisciplinary knowledge into the creative architectural design process. Done in collaboration with the Danish architecture office 3XN and Centre for IT and Architecture (CITA) at The Royal Danish Academy of Fine Arts, School of Architecture, Design and Conservation. The project investigates how daylight quality, solar radiation control, and visual and thermal control can be design parameters in the initial design phase. The research is based on practical experiments performed in the competition department at the architecture office 3XN. These experiments are carried out in close collaboration with daylight consultants at Esbensen Engineers, DTU, and the Danish Technological Institute.

Today 80 % of vital design decisions are made during the first 20 % of the design process [Theßeling et al. 2008]. These early decisions concern the work of architects involved in the initial design phase. Today the architecture profession is facing increasing demands for sustainable solutions and so, daylight conditions and indoor comfort have come into focus as never before. The design processes and creative work methods of architects are challenged by the technical processes involved in calculating daylight. The digital toolsets for analysis and simulation have for years been used primarily by engineers and have been applied very late in the design process. At this stage it is costly and often too late to change the overall building design [Liebchen 2002]. Developments in recent years have made analysis and simulation tools for daylight available for architects. In spite of this, these tools are rarely being used in the early design phases, where decisions mainly rely on “rule-of-thumb” methods and past experience.

In recent years programs like Grasshopperand Generative Components2 have made parametric tools with visual programming interfaces accessible to architects at low cost. This gives the opportunity to produce customised toolsets where simulation and architectural design can happen simultaneously. This research project investigates if parametric tools can be used to simulate daylight thereby increasing communication between members of the design team and improving early design decisions.

The entire dissertation can be read at http://issuu.com/parametri/docs/afhandling_tore_banke_web (Thesis in Danish, English Summary)