Twenty-Five Years of Daylighting Research at EPFL

The Solar Energy and Building Physics Laboratory (LESO-PB) of EPFL has been at the forefront of daylighting research for more than 25 years. It initiated the creation of a Swiss Daylighting Competence Centre in 1989 by launching several interdisciplinary research programmes involving physicists, ophthalmologists and architects (LUMEN, 1989). Daylighting architectural design was addressed as a first target, leading to the setting-up of computer daylighting design tools combining building architectural typologies with fuzzy logic (Paule, 1999). New generations of sun and sky simulators (automated heliodon, scanning artificial sky) were also set up, improving the reliability and accuracy of daylighting performance assessment of buildings using physical models (Michel, 1995) (Thanachareonkit et al., 2005). Other European and US research institutions such as University of Urbana-Champaign/USA, Politecnico di Torino/Italy and the Belgium Building Research Institute replicated these technologies. Advanced computer software (Radiance programme), based on ray-tracing techniques (Scartezzini et al, 1994), were developed in collaboration with Lawrence National Berkeley Laboratory (LBNL) and Fraunhofer Gesellschaft (FhG) to address the complexity of light propagation in buildings and daylighting systems (Erhorn et al., 2000) (Kaempf and Scartezzini, 2004).

Future Outlook and Perspective in Daylighting Research at EPFL
Non-imaging optics, well known for its application to solar concentrators (Welford and Winston, 1989), was also used to set up a novel design approach for advanced daylighting systems, the so-called Anidolic Daylighting Systems (ADS) (Scartezzini and Courret, 2002). They were implemented on different experimental test facilities (DEMONA daylighting test modules, LESO solar experimental building) in order to assess their luminous performance and users, acceptance at full scale (Altherr and Gay, 2002) (Linhart et al., 2010). The optimal integration of ADS with high efficacy light sources (CFL, LED) and efficient luminaries based on nonimaging optics in an office room was successfully achieved (Linhart and Scartezzini, 2011): it led to lighting power densities as low as 3 W/m2 (instead of 12-15 W/m2) together with improved occupants’ visual performance and comfort, as well as larger circadian light components compared to electric lighting (Linhart et al., 2009) (Linhart and Scartezzini, 2010). A bidirectional goniophoto meter, based on digital imaging techniques and showing significant advantages compared to conventional devices, was set up to assess the luminous properties of Complex Fenestration Systems (CFS) (Andersen et al., 2001) (Thanachareonkit at al., 2010). Combined to the visualization features of a novel CFS computer simulation software (Geronimo programme), it will lead to new analysis and design capabilities for advanced daylighting systems at EPFL (Kaempf and Scartezzini, 2011). The opportunity to investigate the psycho-physiological aspects of (day-)light, which affect the human health and well-being, was recently taken at EPFL through the creation of a “Post-Doctoral Fellowship in Daylighting and Perception” supported by the Velux Foundation (Switzerland). The more recent creation of a new interdisciplinary laboratory at EPFL, focused on “Performance-Integrated Design” and led by Professor Marilyne Andersen, a former PhD student at LESO-PB, will also contribute to strengthen the State of Union in Daylighting at EPFL by fostering daylighting design among students of architecture and professionals.

Jean-Louis Scartezzini was born in 1957 in Lausanne and graduated from the EPFL (Swiss Federal Institute of Technology, Lausanne) with a diploma in Physics in 1980. In 1986 he obtained a PhD in Physics for a thesis presented at the EPFL Department of Physics and written in part at Colorado State University in the United States. In 1991, Jean-Louis Scartezzini was nominated Professor in Building Physics at Geneva University, then, in 1994, he was nominated Professor at the Department of Architecture of the EPFL, where he heads the Solar Energy and Building Physics Laboratory. From 2002 to 2009 he furthermore headed the Institute of Infrastructures, Resources and Environment (ICARE) as well as the Doctoral School Programme Environment. He is the author of more than 200 scientific publications and member of several federal commissions and international work groups as well as associate editor of two scientific journals.

Our lives are ruled by time and we use time to tell us what to do. But the digital alarm clock that wakes us in the morning or the wrist-watch that tells us we are late for supper are unnatural clocks. Our biology answers to a profoundly more ancient beat that probably started to tick early in the evolution of all life. Embedded within our genes, and almost all life on earth, are the instructions for a biological clock that marks the passage of approximately 24 hours. Biological clocks or “circadian clocks” (circa about, diem a day) help time our sleep patterns, alertness, mood, physical strength, blood pressure and much more. Under normal conditions we experience a 24-hour pattern of light and dark, and our circadian clock uses this signal to align biological time to the day and night. The clock is then used to antici-pate the differing demands of the 24-hour day and fine-tune physiology and behaviour in advance of the changing conditions. Body temperature drops, blood pressure decreases, cognitive performance drops and tiredness increases in anticipation of going to bed. Whilst before dawn, metabolism is geared-up in anticipation of increased activity when we wake.

Few of us appreciate this internal world, seduced by an apparent freedom to sleep, work, eat, drink, or travel when we want. But this freedom is an illusion; in reality we are not free to act independently of the biological order that the circadian clock imparts. We are unable to perform with the same efficiency throughout the 24h day. Life has evolved on a planet that experiences profound changes in light over the 24h day and our biology anticipates these changes and needs to be exposed to the natural pattern of light and dark to function properly. Yet we detach ourselves from the environment by forcing our nights into days using electric light, and isolate ourselves in buildings that shield us from natural light.

Russell Foster is Professor of Circadian Neuroscience and the Head of Department of Ophthalmology at Oxford University. Russell Foster’s research spans basic and applied circadian and photoreceptor biology. For his discovery of non-rod, non-cone ocular photoreceptors, he has been awarded numerous prizes, including the Honma prize (Japan), Cogan Award (USA) and Zoological Society Scientific & Edride-Green Medals (UK). He is coauthor of Rhythms of Life and Seasons of Life, popular science books on biological rhythms. In 2008, he was elected as a Fellow of the Royal Society.

Within the last decade it became evident that light through the eyes is essential for not only visual but also non-visual photopic functions. One of the most important non-visual functions of light is the daily entrainment of the circadian clock by environmental light conditions. As most people spent the majority of their time inside buildings, room light quality defines many physiological and behavioral functions in addition to vision related properties. This is true for acute responses to light as well as for circadian (and probably even longer lasting) light effects. Another emerging question is to what extent visual and nonvisual functions might interact. We tested whether visual comfort is associated with subjective alertness, mood and physical wellbeing. By comparing these effects under two different office lighting conditions in healthy young subjects during daytime, we found that associations of visual comfort with alertness, mood and wellbeing were not only dependent on lighting conditions but also on time of day. We also found repercussions of different light conditions during the afternoon on cognitive performance in the evening. We conclude that for optimum environmental lighting conditions both visual and non-visual aspects of light need to be integrated into architectural and building science.

Mirjam Münch, received her Ph.D. in Neurobiology from the University of Basel in 2006, under the supervision of Prof. Dr. C. Cajochen and Prof. Dr. A. Wirz-Justice, (Centre for Chronobioloy, Psychiatric University Clinics, Basel). For her doctoral thesis she investigated circadian and homeostatic effects of age and monochromatic light on human sleep. After graduation, she left to the US for a position as a Post-doctoral Research Fellow at the Brigham & Women’s Hospital (Division of Sleep Medicine), at Harvard Medical School in Boston (Prof. Dr. J.F. Duffy). At the end of 2008 she moved back to Switzerland and began as a Fellow of the VELUX Foundation at the Laboratory for Solar Energy and Building Physics, (EPFL) in the research group ‘Daylighting and Perception’ led by Prof. Dr. J.-L. Scartezzini. Since joining this interdisciplinary group, several research projects were designed and a new scientific network in the framework of (day-) light and circadian physiology was built up. The aim of her current position at LESO-PB is to bridge the gap between neuroscience and circadian physiology on the one hand and potential applications in building science and architecture on the other hand.

To study the amount of light entering the eye and its effects on office workers, measurements were taken from 23 office workers over a period of seven consecutive days. Two parameters of visible light were recorded: (i) illuminance and (ii) irradiance of the blue spectral component. Every evening before going to bed, a questionnaire had to be filled out, containing scales relating to the mood dimensions of pleasure and arousal, questions about the previous night’s sleep and a rough time table with information about the person’s whereabouts during the day. The exposure to light on workdays is regular but it varies strongly on days off. No evidence could be provided for the influence of age, sex or seasonal affective disorder (SAD) scores on the daily exposure to light of office workers. The amount of light entering the eye during the day appears to have a positive impact on sleep quality the following night. Pleasure and arousal were not significantly associated with daily light exposure.

Sylvia Hubalek studied architecture and environmental engineering at TU Munich. After graduation in 2000, she started to work at Ebert-Ingenieure in Munich where her responsibilities included planning, consulting and simulation in the field of daylight and artificial lighting. While working full time, she continued her education at TU Ilmenau where she attended a programme on “Light Application”under the supervision of Prof. Dr. Dietrich Gall. As of autumn 2003, she was employed as a Scientific Assistant at ETH Zurich, Switzerland. She initially worked at the Institute of Hygiene and Occupational Physiology under the supervision of Prof. Dr. Dr. Helmut Krueger. In autumn 2005, she transferred to the Centre for Organizational and Occupational Sciences under the supervision of Prof. Dr. Theo Wehner. At ETHZ she was involved in environmental ergonomics with her supervisor Dr. Christoph Schierz. In addition to providing consulting services for lighting at workstations and managing training courses for students, she did research on “Light and Humans”. The results were included in her PhD thesis and other publications. Since May 2007, she has been working at the Institution for Statutory Accident Insurance and Prevention (Berufsgenossenschaft), where she is involved in occupational accident prevention. She is a member of TC 3-46 “Research Roadmap for Healthful Interior Lighting Applications” at CIE.

In a previous paper I argued that any enthusiasm for modifying lighting practice to take account of the impact of light exposure on human health would be premature. Since that paper was written enthusiasm for this course of action has waned somewhat. This is not because enhancing human health is considered a bad thing but rather because of the ever-growing physiological complexity that has been revealed and the increasing concern that circadian disruption might be involved in the development of various cancers. But there has been progress. There are now models of the spectral sensitivity of the circadian system and some estimates of the threshold amount of white light required to influence it. There is also available equipment for measuring and recording circadian light exposure, in the field, over several days. This equipment offers the possibility of identifying lighting conditions that lead to circadian disruption. As a result of these developments, the use of light exposure as a means of enhancing health for at least some people remains a possibility but not a certainty. Until a full understanding of the non-visual effects of light exposure is available, the best approach to lighting for human health is to try to replicate the conditions under which mankind evolved – daylight by day and little light at night.

Peter Boyce earned his doctorate in Reading University, England in 1965. In 1966-1990 he worked as Research Officer in Electricity Council Research Centre, England. In 1990-2004 he was the Head of Human Factors at the Lighting Research Center, Rensselaer Polytechnic Insitute, New York. Since 2004 he has been working as an independent consultant. His current interest areas are photobiology, lighting for elderly, security lighting, light pollution and lighting quality. He has published the book Human Factors in Lighting as well as many papers in recognized journals.

Following the discovery that intrinsically photoreceptive retinal ganglion cells are responsible for entraining circadian rhythms to patterns of light and dark, and furthermore that those cells are most sensitive to short-wavelength optical radiation, considerable attention has focused on the possibility of using daylight to achieve a healthy lit environment. Daylight is rich in that area of the spectrum, and bright at the times of day that seem most important to these processes. The science has moved rapidly in the ten years since the last substantive reviews of the state of the art on the health and well-being effects of daylight and windows, making it time for a renewed examination of the literature. Moreover, there has been scant attention paid to the role of daylight in residential buildings. This presentation will give a brief overview of three processes by which windows and skylights in homes might influence health and wellbeing: light dose, view, and architectural aesthetics. Windows and skylights also influence long-term sustainability, through which they indirectly will affect health and well-being of present and future generations. The presentation will conclude with suggested research directions to bring together these strands, as will be necessary for the derivation of practical recommendations.

Jennifer Veitch, Ph.D., Senior Research Officer, National Research Council of Canada Institute for Research in Construction (NRC-IRC). She initiates, leads, conducts, and reports on investigations into the effects of buildings on occupants’ satisfaction, well-being, health, and performance. Jennifer A. Veitch has also chaired CIE Technical Committee 6-11, “Systemic Effects of Optical Radiation on the Human” to the successful completion of the first  international consensus report on the non-visual effects of light on humans and their potential architectural applications, Ocular lighting effects on human physiology and behaviour (CIE 158:2004).

Previously thought of mainly in terms of task illumination and aesthetics/design, it is now believed that daylight in buildings might serve another purpose as the agent of a number of nonvisual effects. It has long been established that building occupants prefer an environment with daylight and views to the outside in preference to predominantly artificially lit spaces. In addition to these subjective preferences for daylit spaces, it is now firmly established that daylight has measurable biochemical effects on the human body, in particular with respect to maintaining a healthy sleep-wake cycle, i.e. circadian entrainment. Recent findings on these non-visual aspects of occupant exposure to daylight have led to a reconsideration of the function of daylight in buildings. Could the quality and nature of the internal daylit environment have a significant effect on the health of the human body which can be proven through the measurement of, say, hormone levels? Evidence is indeed suggestive of links between daylight exposure and both health and productivity indicators. The duration, intensity and spectrum of the light received at the eye are the principal factors determining the suppression in the production of melatonin by the pineal gland, and thus a key component in the entrainment of the circadian cycle – the maintaining of which is believed to have significant short and longterm beneficial health effects. Illumination levels are also believed to influence levels of alertness. An important factor in these considerations is the time of day when the light is applied. Compared to the luminous efficiency function of the eye, which has a peak value at 555nm, the action spectrum for the suppression of melatonin is known to be shifted to the blue end of the spectrum and has a peak around 450nm. Recent advances in experimental photo-biology have yielded sufficient data to calibrate models that allow, in principle, the quantification of the daylight stimulus required to induce non-visual effects.

In this presentation we describe the formulation of a model to predict the non-visual effects of daylight in buildings and demonstrate its application to a residential dwelling under various different building configurations and prevailing climates. These different building scenarios are used to show the sensitivity of the predicted quantities to various design and contextual (i.e. location and orientation) parameters. The model is founded on the climate-based daylight modelling (CBDM) approach, i.e. the prediction of absolute levels for luminous quantities over a full year and founded on standardised climate files. The CBDM approach was given several enhancements to account for the difference between the standard luminous efficiency function and the action spectrum for the suppression of melatonin. The various modelling procedures and assumptions are described in the presentation, and a novel means of visualising the ‘circadian potential’ of a point in space is presented.

John Mardaljevic is a Reader in Daylight Modelling at De Montfort University, Leicester, UK. His first degree and higher qualifications are: a BSc in Combined Physics with Maths, an MPhil in Astrophysics and a PhD in Daylight Simulation. Mardaljevic’s first significant contribution in the field of daylight modelling was the validation of the Radiance lighting simulation program under real sky conditions. Mardaljevic went on to pioneer the  development and application of what has become known as climate-based daylight modelling. As an acknowledged world leader in daylight modelling, he was invited in 2007 to join the panel convened to revise British Standard 8206: “Daylight in Buildings”. In December 2008 the Board of Administration of the International Commission on Illumination (CIE) approved the formation of Technical Committee 3-47: Climate-Based Daylight Modelling following a proposal made by Mardaljevic earlier that year. In 2010 Mardaljevic was appointed ‘UK Principal Expert on Daylight’ for the European Committee for Standardisation CEN /TC 169 WG11.

On May 3rd, the VELUX Daylight Symposium introduced an international Academic Forum for PhD students, and the forum was used as a platform where students could share and exchange experiences in the field of daylighting research. The Academic Forum were attended by 30 PhD students from 9 countries. Together with the students, a panel of scientific experts supported the discussion. The experts invited were Barbara Matusiak (N), Marilyne Andersen (CH), Jennifer Veitch, Peter Boyce (UK), and Steve Fotios (UK).

Within the Academic Forum, we centered our constructive discussion of the students research projects, with focus on what was the key problems/challenges; how could I solve it? What was the methodology I would use?; Who faces these problems/challenges?; and Why should I solve it?. This presentation will highlight the discussions within the Academic Forum, and provide a general overview of all the PhD projects, which will show the great diversity of topics and methodologies. Further discussion will focus on how we maintain a ‘working’ forum among the PhD students.

Steve Fotios, PhD, Professor, School of Architecture at Sheffield University, UK. Steve Fotios leads research of lighting and visual perception, and his research focus on investigating interior and exterior lighting with a strong emphasis on methodology. Exterior lighting research has focussed on pedestrians, and how lighting affects reassurance, ability to detect pavement obstacles, and ability to recognise the intent of other people. Interior lighting research has examined spatial brightness and glare on display screens.

I take my title from Louis Kahn’s observation that, “the measurable is only the servant of the unmeasurable”. One of the most important achievements of applied science in the nineteenth and twentieth centuries has been to quantify and codify human requirements in buildings. This has been particularly successful in the field of lighting design, where standards of illumination, design tools and rules-of-thumb make a significant contribution to practical design. But there is much more to successful daylighting design than the quantitative. As, once again, Louis Kahn observed, “Architecture comes from the making of a room. A room is not a room without natural light.” Natural light thus becomes the key to the definition of architecture itself. The question that arises is how may we capture and communicate the unmeasurable element of daylight in buildings? In my research in recent years I have attempted to address this by developing a mode of architectural analysis that connects the quantitative and the qualitative – technics and poetics, as they may be witnessed in works of architecture constructed over the past four centuries (1). The present paper presents examples from these studies.

Dean Hawkes is an architect and teacher. He is emeritus professor of architectural design at the Welsh School of Architecture, Cardiff University and emeritus fellow of Darwin College, University of Cambridge. His books include The Environmental Imagination (2008) and Architecture and Climate (to be published in 2011). His buildings have won four RIBA Architecture Awards. In 2011, he received the RIBA’s international biennial Annie Spink Award for excellence in architectural education.

Designing spaces that are able to balance human comfort, energy-efficiency and well-being in a given climate is a real challenge, yet a problem faced every day by architects and building designers., Within the overall framework of promoting linkages between the engineering and design fields, this talk will discuss new approaches in research and education that are being developed to better integrate building performance considerations in the architectural design process. Daylighting is chosen as a strategic focus for this effort, being inherent to architectural design and one of the main drivers of a building’s technical performance and resulting human comfort and health. The talk will present research and teaching perspectives for the recently founded Interdisciplinary Laboratory for Performance-Integrated Design (LIPID) at EPFL, which include new calculation methods, evaluation tools, instruments and metrics that aim to support this integration effort in the course as well as the lab environments.

Marilyne Andersen is an Associate Professor of Sustainable Construction Technologies at the School of Architecture, Civil and Environmental Engineering of EPFL, and the Head of the Interdisciplinary Laboratory of Performance-Integrated Design (LIPID) that she launched in the Fall of 2010. Before joining EPFL as a faculty, she was an Associate Professor in the Building Technology Group of MIT’s School of Architecture and Planning and the Head of the MIT Daylighting Lab that she founded in 2004. She is the author of more than 50 papers published in peer-reviewed journals and international conferences and the recipient of several grants and awards including: the Taylor Technical Talent Award granted by the Illuminating Engineering Society (2009), the Mitsui Career Development Professorship (2008) and the EPFL prize of the Chorafas Foundation awarded to her PhD thesis in Sustainability (2005).

One of the problems for the near future is the sharp rise of the ageing population. Most people of the growing group of seniors start their senior life as healthy human beings, but they have special differences in respect to young people. During life, the eyes of the human being change clearly. When one wants to create a good visual indoor climate for senior dwellings in order to maintain the quality of life, one should consider the age-related changes of the eyes.

Norms and building regulations have requirements for the physical aspects of buildings in order to get a good comfortable indoor environment, but there is no special discrimination in these standards between buildings for young people and buildings for seniors. For the well-being of seniors it has a high priority now to develop good design principles for senior dwellings and elderly homes.

A good indoor environment can be preventive for different problems, which are always related with elderly people. Good daylight situations can give less depressive complaints. A bad visual environment results in more fall incidents. And in general one can say that the dominance of one’s owns situation can be stimulated by good lighting situations. There are several studies for a good visual environment for elderly with dementia or low vision, but our research concentrates itself to the visual environment for healthy seniors.

Knowing the ageing of the eyes, we decided to do a pilot study to observe the real visual environment in senior homes in the Netherlands. Measurements were done in 11 senior dwellings and 4 nursing homes and seniors were asked to answer questions about their visual environment. In the nursing homes, some caretakers were asked too. For this research it was very needed to ask the seniors themselves about their building environment, because subjects in building physical experiments are mostly younger ones.

The research showed here is an ongoing study at our faculty with graduate students. It was a big challenge for the research students to ask questions in a good way, because in the beginning of this pilot study they already learned, that some elderly are happy with the visit of the researcher, but not always give adequate answers on the research questions.

Truus de Bruin-Hordijk did her graduation study and her PhD study in Solid State Physics. She worked as a teacher at a secondary school and a high school, and has now been working for fourteen years at the Climate Design/Building Physics group of the faculty of Architecture of the Technical University of Delft. Today she is an associate professor responsible for the daily supervision of the Building Physics group of the faculty. Her research topics are visual and thermal qualities of daylight in inner spaces and urban physics aspects regarding light, sun and wind. Her aim is to contribute to achieving a healthy, comfortable and sustainable built environment. Within this context, and focus on ‘Daylight’ research. She is also the research leader of the ‘Comfort’group of the Building Technology department. This group is doing research for the thermal, acoustical and visual comfort of indoor and outdoor spaces. Finally, she is a member of several daylight committees and workgroups, as well as chairman of the Dutch Standard committee.

There is currently under development a European standard on daylight. The standard when complete will form part of set of European Standards in the area of lighting application created by CEN and it will be closely related to EN 12464-1 – Light and Lighting, Lighting of Work Places, Indoor Work Places and EN 15193 – Energy Performance of Buildings, Energy Requirements for Lighting. The current working group developing the standard is made up of 22 experts representing 10 different national standards bodies.

Work on the standard has only just started but the group has already planned out the shape of the document. It will cover all building types including dwellings and workplaces and will include a special section for people with limited mobility that may not be able to get out. The main topics that will be addressed are view out, daylight available to a building on a given site, the daylight performance of the building and the health impact of daylight.

Whilst probably the best way to control daylight in buildings is climate based modelling; there is not sufficient experience of using such techniques to enable the writing of standard and so the basis of the recommendations will be the use of daylight factor. However, as daylight availability varies so much across Europe the daylight factor metric will have to be adjusted so suit different climates. The standard will give guidance on how to size windows to meet a given daylight factor to allow compatibility with a number of existing national daylight standards which control window size.

It is recognised that this standard will not of itself improve the use of daylight as most good buildings will already have better daylight than that it recommends, the function of the document will be to stop the buildings with poor daylight being built.

Peter Raynham is the Lighting Education Trust Lecturer. He has been working in the area of Light and Lighting since 1976 and has been at the Bartlett since 1996. His research interests cove the whole scope of lighting ranging from street lighting to lighting in schools, the use of daylight and lighting calculations. He is currently running an EPSRC funded project looking at glare associated with street lighting and has recently won another bid to look at Mesopic lighting for pedestrians (MERLIN). Peter is active in a number of professional and standards bodies and is the president elect of the Society of Light
and Lighting.

Within contemporary urban environments, daylight is increasingly being restricted and supplemented with artificial light, resulting in a loss of connectedness to the natural environment. If our physiological and the psychological expectations are to be met, architecture will need to develop fresh techniques in working with daylight, as well as create a closer dialogue with science, in order to achieve a true state of well-being in people.

So far, architects’ concern for daylight has been driven by a need to control the indoor climate, to maintain comfort, and to penetrate the interior space with light. The primary interface and filter for daylight, has been the window. Glass permitted the window to fuse into the architectonic form, to provide enclosure, to control indoor temperature, and to transmit and celebrate the qualities and benefits of daylight. Glass has also been the measure of how individual architects have related their architectural vision to the well-being and comfort of users and inhabitants.

In contemporary terms, the windows have now become the building, and glass the interface for future engagement between daylight and living, between the physical and the psychological, between comfort and well-being. Building on the legacy of Frank Lloyd Wright and Mies van der Rohe to present day Peter Zumthor, we are now seeing a new era of humane and sustainable architecture. This era speaks of the architect as a professional polymath, capable of embracing complexity and change; and of the architect as a humanitarian who is concerned with the value of daylight as a life giving substance.

We now need to initiate advanced research into a new field that we might call the ‘anthropology of daylight’, or the ‘culture of transparency’ in all buildings, and to seize the opportunity to enjoy a greater sense of well-being. But in doing so, we must also recognise that this task cannot be left to architects alone. We need teams of specialists to contribute and expand our knowledge and develop new methodologies and carry out live rather than laboratory experiments. It is time to conceive of buildings that are totally embracing daylight for its power and energy, for its visual delight and beauty, and for its healthy environmental effects.

Brent Richards is an architect, designer, academic, and polymath. Currently he is CEO of The Design Embassy Europe, a transdisciplinary creative consultancy in London that focuses on architecture, spatial design and experiential environments. He has conducted pioneering work on the advanced use of glass technology for which, in 1995, he was awarded the International Benedictus Award (USA) by Du Pont and the American Institute of Architects (AIA).

I have always known somewhere deep within myself, lies light. In the darkest hour of the night, during the silence of a sunrise or as the sunlight filters into the thicket of a forest, I have felt the presence of this light, of myself, of my own being come forth. Moments as such hold the deepest human experiences and it is in pursuit of such moments that I continue my journey. Sometimes, I have found these moments in manmade works too, in architectural space and artistic experience. These works, from Turrell’s installations to Zumptor’s Therme, have touched me deeply and made me feel free, present and human. The presence of a certain light quality in their work speaks me in a way words cannot describe. I’ve contemplated these ideas for some time, and sought to explore them in my own ways. What is it about these spaces that make them so evocative and touching? Can I as a designer, also create such work? To answer these questions, perhaps we must ask the most basic question: What is the primary relationship between man and light?

Vellachi Ganessan has explored light and lighting from many perspectives, starting from her architectural background to her involvement in the theatrical lighting scene to her work as a light artist. Her philosophy in lighting stems from her research into the primal relationship between light and man. Having recently graduated with a master in Architectural Lighting Design from the Royal Institute of Technology (Sweden), she is currently working for ARUP Singapore as a lighting designer. She is also involved with conducting workshops and lectures in her local community.

Knowledge about daylight rhythms will enable greater daylight utilisation in buildings. The goal of building design is to create spaces with maximum use of daylight, within comfort limits, while assisted by systems that respond adequately to changing daylight conditions. The development of electric lighting caused humans to move indoors and removed people more and more away from natural lighting and its triggers. Indoor lighting quality and efficiency can be improved when electric lighting and shading does not respond to human rhythms, but to naturally occurring environmental (daylight) rhythms. Possible relationships between outdoor conditions, including their frequencies, and human rhythms are of particular interest in order to have the ability to control buildings based on frequencies. In order to understand the dynamics of natural light with regards to human needs, measurements were performed. In these experiments daylight conditions were studied in a test room with two different window openings on days with diverse weather conditions. The results were linked to data collected by Actiwatches used to record spontaneous motor activity (SMA) and worn by healthy human beings. For all 24-hour data (daylight and human) Fast Fourier Transform (FFT) was used in order to transform time-dependent data into a sum of sinusoidal base functions. Results show that different lighting control strategies are necessary for different weather conditions in order to satisfy naturally occurring human rhythms.

Myriam Aries is currently working with the Energy, Comfort, and Indoor Environment group of TNO Built Environment and Geosciences. After a Building Technology master project related to daylight and visual comfort at the TU Delft, she conducted a Ph.D. research project at the TU Eindhoven with regard to human visual and nonvisual lighting demands and the realization of healthy lighting. She expanded her knowledge while working as post doctoral fellow within the lighting group of the NRC Canada.

Laurens Zonneveldt is currently working with the Energy, Comfort, and Indoor Environment group of TNO Built Environment and Geosciences. He studied Physics and Meteorology in Utrecht and has been working for over 25 years in lighting research with the focus on daylighting. Over the years, he has participated in numerous international projects on energy efficient lighting and visual comfort.

Daylight and its dynamic qualities are fascinating! Natural light is a fundamental factor in architecture. It affects the visual appearance of a space and has strong impact on aspects like health and energy efficiency. Still there is a lack of awareness for the potential of natural light.

Thinking about sustainable design most clients and architects are not aware that energy consumption for artificial light can add up to 75% of the overall consumption (Brandi 2005: 16).

The goal is to improve communication about daylight and to plead for the integration of daylight aspects at an early stage of the design process. Most often the design focus is on adding artificial light which results in higher energy consumption. The first thought though should always be on daylight. That means to find the right amount, direction and places for daylight to penetrate the building. This subtractive approach must always be the first step before adding more and more artificial light. Daylight design is not only the optimisation of glass façades, but also about aspects like considering the rooms’ depth and its type of usage.

To raise awareness means to improve the communication about daylight in design and spread the knowledge about its relevance. Good daylight design is not always about complex calculations but rather about early thoughts on it! It is crucial to let as many clients and architects as possible know that using rules of thumb at an early stage can already strengthen their design to save resources and money by saving energy.

Ulrike Brandi was born in 1957 in Bad Bevensen. A student of industrial designer Dieter Rams, Ulrike Brandi’s work is rooted in problem solving. She is the founder and director of Ulrike Brandi Licht GmbH. The design and consultation services provided by Ulrike Brandi Licht cover five areas: artificial lighting design, daylight design, luminaire design development, masterplanning and event/show lighting. Special services include the design of lighting concepts in close cooperation with architects and clients, which furnish buildings and open spaces with a distinct mood. Experience gained in over 600 worldwide projects is applied during the design process and finding technical solutions.

“Light defines the journey of our lives”. You can already experience this by watching the path of the sun in a room”. American architect Will Bruder has been living and working in Phoenix, Arizona. His architecture is a reflection of the surrounding desert landscape, its shapes and colours, and its daylight. In his work he is attracted by the dialogue between the pragmatic of making things, and the poetic of experiencing them: “I always work to let the ordinary become the extraordinary. Whether I work with a concrete block, a piece of wood or with ‘ordinary’ light, the key question is always, how to transform that ordinary thing into spaces and memories that achieve the sense of something extraordinary. Another aspect is how my buildings relate to their surroundings. When you look across the Arizona desert, your first perception is of how the buildings emerge from the earth. Your eye is drawn up along the surface of the building, towards the line where it kisses the sky. And that line tells you everything. This phenomenon is common to the desert places of the world, whether it is Morocco, the Middle East or Arizona. Our best buildings are the ones that form a perfect dialogue between shadow and light, and between the earth and the sky.”

Will Bruder
For 40 years, Will Bruder has explored inventive and contextually exciting architectural solutions in response to site opportunities and user needs. Will is a craftsman in his concern for detail and building processes, and a sculptor in his unique blending of space, materials, and light. With over 500 commissions the work has celebrated the craft of building in ways not typical in contemporary architecture. Will strives to invent form specific to function and client aspiration. Through his creative use of materials and light, Will’s ability to raise the ordinary to the extraordinary is renowned. Will’s architecture has been widely published in the United States, Europe, and Japan.

This presentation summarizes results from a series of recently finished and ongoing projects at the GSD-square research initiative at Harvard University, Graduate School of Design. In collaboration with the Fraunhofer Institute for a Solar Energy Systems a simulation-based ‘daylighting dashboard’ was developed that simultaneously evaluates annual daylight availability, visual comfort and energy use in daylit spaces . The purpose of the dashboard is to visually present simulation results to simulation nonexperts.

A highly optimized simulation workflow for designers based on Daysim/Evalglare/Radiance for annual daylight availability and glare simulations as well as EnergyPlus for thermal load calculations has been implemented as a plug-in for the popular Rhinoceros CAD environment.

The plug-in, called DIVA-for-Rhino, uses the Daylight Glare Probability (DGP) concept to predict the likelihood of an occupant experiencing discomfort glare form daylight. In a follow up project DGP simulation results were tested against five other glare indices and it was found that DGP yielded the most plausible results in the investigated spaces and lighting conditions. In an attempt to deal with multiple positions and view directions simultaneously, the concept of an ‘adaptive zone’ was further introduced within which building occupants may freely adjust their position in order to minimize the effect of glare.

Finally, an attempt was made to develop design tools that not only evaluate what has already been designed but that provide direct advice as to where the weaknesses of a specific design lie. A new algorithm called SHADERADE was developed that directly supports the design of energy efficient static shading systems. For a South-facing office it has been shown that the algorithm is able to consistently generate shading systems with improved thermal performance vis-àvis existing methods.

Christoph Reinhart is a building scientist and architectural educator working in the field of sustainable building design and environmental modeling. Before joining the GSD in 2008, he had worked for over a decade as a staff scientist at the National Research Council of Canada and the Fraunhofer Institute for Solar Energy Systems in Germany. He holds a doctorate degree in Architecture from the Technical University of Karlsruhe and master degrees in Physics from Albert Ludwigs Universitaet, Germany, and Simon Fraser University, Canada. Dr. Reinhart’s research expertise is in daylighting, passive climatization and the influence of occupant behavior on building energy use. The main outcome of his work are design workflows, tutorials and performance metrics that accommodate the complementary use of rules-of-thumb and simulations during building design.He is the main developer of the Daysim and DIVA-for-Rhino sustainable design tools and has led a number of simulation studies, field studies and occupant behavior surveys. He is on the editorial board of the Journal of Building Performance Simulation and guest-edited a special issue on ‘Daylighting’ for Energy and Buildings. He has authored and co-authored over 90 scientific articles including three book chapters and chaired the scientific committee for esim 2008. Between 2005 and 2007 he was a member of the Technical Advisory Group for LEED-Canada and an Adjunct Professor at the School of Architecture at McGill University. From 2002 to 2006 he was a Subtask Leader within the International Energy Agency’s (IEA) Solar Heating and Cooling Programme.

Within the last twenty years a growing body of scientific documentation has developed suggesting that the physical environment on hospitals have an impact on patients’ and staffs experience of well-being, stress and the general outcome. As Denmark is in the midst of investing and planning hospital facilities replacing the facilities designed and built in the sixties and seventies, this research is especially relevant currently.

The research project ‘Healing architecture’ compiled and reviewed research that links the physical environment on hospitals with patient and staff outcomes. The project addressed the question whether architectural design has a healing potential. The objective was to develop a tool that could give an overview of this research for the building clients and decision-makers responsible for the huge investments in future hospitals and healthcare facilities in the coming decade. Drawing upon phenomenological architectural theory a categorical model was developed that facilitated sorting and communicating the research findings. The project concluded that the research findings can be used to inform the decision-making in the briefing and design process. Especially well documented was the impact of light, sound, views to green outdoor areas on the experience of pain, stress and days of admission as well as on the general well-being of patients. It was therefore concluded that architecture can support the healing process of the individual.

Anne Kathrine Frandsen, Architect, PhD and researcher at The Danish Building Research Institute, Aalborg University, DK department of Construction and Health. Her research focuses on design processes and the impact these can have on architectural quality and on the healing potential of architectural design. She is one of the main authors of the publication ‘Healing architecture’ an extensive literature study of research linking physical environments on hospitals with patient and staff outcomes and their experience of stress.

Prior to the advent of buildings, humans lived immersed in nature. Daily activities were aided or constrained by the presence or absence of daylight and by qualities of light that signalled time and weather. Our physiological systems – especially our sleep-wake cycles – were in synch with the diurnal rhythms of daylight, as were our emotional responses to light and darkness. The strong, consistent preference for daylight in our built-up environments today suggests that evolutionary pressures are likely to be influencing our responses.

Although all our sensory systems acting together were important to survival, the visual system is our primary mode of gathering information. Thus, light must have played a powerful role in information processing and survival. In ancestral habitats, light was likely to have had several key functions that are relevant to the design and operation of built-up environments.

Light provides information for orientation, safety and surveillance, interpretation of social signals, identification of resources and awareness of hazards. Whether it is the changing colour of light associated with sunset or storms, the movement of fire or lightning, the brightness in the distance that aids planning and movement, or the sparkle of light off water – all these aspects of light have played a role in helping our ancestors make decisions about where to go, how to move through the environment, what to eat, and how to avoid dangers. The life-like and life-supporting qualities of daylight strongly suggest that daylight is a basic human need, not a resource to be used or eliminated at the whim of the building owner or designer. The presence of daylight and sunlight in buildings clearly affects our psychological and physiological experience of place. Its absence creates lifeless, bland, indifferent spaces that disconnect us from our biological heritage.

Judith Heerwagen, PhD, is an environmental psychologist in Seattle, Washington. She is an affiliate faculty member in the Department of Architecture at the University of Washington where she has co-taught seminars on bio-inspired design and sustainability. She has written and lectured widely on the human factors of sustainable design, including health, psychological impacts and productivity. She is co-editor of Biophilic Design: The Theory, Science and Practice of Bringing Buildings to Life (Wiley, 2008).

Outro discussion by James R. Benya (above) and Marc Fontoynont (below).