Designing Healthy Daylight Into Buildings

by Caroline Paradise, Welsh School of Architecture, Cardiff University, United Kingdom

This work investigates the use of daylight by architects in order to provide internal environments that support health and well-being. In particular, it ascertains possible implications of improvements to the thermal performance of glazing on this resource and whether specific types of glazing system allow an appropriate quality and quantity of light transmission to the internal environment.

As well as considering how we evaluate the daylight available we also need to consider the transition of light to internal environments. Glass and glazing system design has developed significantly in response to requirements of improved thermal performance altering the reflectance, absorbance and transmission of light through these glazing systems. As the threshold between external natural light levels and internal lighting environment, glazing systems are the primary determinant of the quality and quantity of daylight that the building occupants receive.

These findings could have a significant impact on the design of buildings, in particular those where their occupants spend substantial time inside, such as hospitals. The apparent connections between health and natural light suggest that the design of these buildings particularly ought to take this into consideration as a major design driver.

Evidence-Based Daylight Design of Hospital Operating Rooms (ORs)

by Choong-Yew Chang, University of Sheffield, United Kingdom

In contemporary hospital design, ORs and other specialist equipment spaces are frequently positioned inside the deep plan without accessibility to daylight. Numerous studies have shown that daylight assists patient in reducing stress and depression, and more daylight is linked to greater job satisfaction of hospital staff. Incorporating daylight in OR can potentially provide positive impacts on surgeons since surgical operations require long working hours and intense focus. However, a research in 2009 reported lower visual satisfaction in the audited ORs with daylight, compared to ORs without daylight. Therefore, this study is designed to compare two sets of completed examples of ORs: one set with daylight provision and the other without daylight provision to understand the effects of daylight on staff and patient in OR environment. The aim is to investigate the interrelationship between daylight performance and staff productivity or patient health outcomes. A multi-methods approach is used to collect data for analysis, and measurements of daylight are carried out to establish the characteristics of daylight provision. Staff productivity and patient health outcomes, for example medical errors, will be evaluated based on hospital records and other healthcare information systems. Surveys of clinical staff will be conducted to understand the level of work satisfaction in ORs with daylight and ORs without daylight. Computer simulated models of ORs will be used to examine different daylight design interventions. Results from the study will help with the development of suitable daylight design tools and guidance for ORs.

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.

Light and Dark Rhythms: Daylight and Artificial Light Qualities for the Design of Future Spaces

by Federico Favero, Royal Institute of Technology, Sweden

Most of research in chronobiology and lighting science is performed under artificial lighting conditions. The aim of this case study was to investigate and compare the effect of the exposure to daylight and artificial light on people’s sleepiness, energy, mood and activity level. Subjects, separated in two groups, experienced two radical lighting solutions for three days in a row, 8 hours each day: one group experienced a room lit only with artificial light; the second experienced a room lit only by daylight. The daylight room was affected by typical variation and low intensity levels of a winter day at the 59th latitude. The artificial room was lit up according to standard with a typical solution for office environment.

Every hour the subjects filled in a semantic differential scale questionnaire on sleepiness (Karolinska Sleepiness Scale), energy and mood. At the beginning and the end of the day the subjects filled in a questionnaire on quality of sleep and general health symptoms. The subjects wore an actigraph (Philips Respironics) for four days, including one day before the experiment. The lighting design qualities were investigated every day through a questionnaire on light and space qualities and one about spatial and temporal associations of the experience made. Vertical and horizontal illuminance was registered through an illuminance meter and a luminance meter.

Preliminary conclusion: after statistical analysis of the data acquired we have observed an effect between light-groups (artificial or daylight room) and the scores on sleepiness and energy level, sleepiness being significantly higher and energy lower in the artificial room. Both groups showed an effect of time of day, sleepiness and lack of energy being more pronounced in the morning. There was also a strong effect of the light-groups on the activity level as measured by the actigraph; actigraphy measurements in the artificial room were significantly lower than in the daylight room.

Through this simple experiment we could observe a strong difference in the impact from daylight and artificial conditions. It was not possible to tease out whether this effect was due to the natural variation of daylight compared to the static condition of the artificial room or to the higher doses that daylight provides during the day. Further research is needed to explore this question.

A Model for Enquiry of Sustainable Homes

by Gitte Gylling Hammershøj Olesen, Aalborg University, Denmark

The aim of the thesis is to develop a Model for Enquiry of Sustainable Homes through exploration of built, in-use, sustainable homes; three Model Home 2020 houses and families living in them. Aiming at complying with the complexity of the world of sustainable architecture, the model employs methods of enquiry through four different perspectives; namely in-situ research, blog research, questionnaire survey and technical measurements. Thereby several aspects of the built environment come together in creating a more complete understanding of what sustainability actually entails.

Roof Windows in Low Energy Buildings – Analyses of Demands and Possibilities for Future Product Development

by Gunnlaug Cecilie Jensen Skarning, Technical University of Denmark, Denmark

Roof windows are flexible regarding light distribution and they allow more efficient utilisation of natural daylight than façade windows do. With these properties roof windows can be expected to have an important role in new and existing low energy buildings. However, the air tight and well insulated low energy buildings define new demands and possibilities for the ideal window product and its use. This creates a strong need for research in the development of cost-effective technologies and solutions that support the ambitious energy requirements of the future, while simultaneously providing desirable daylight conditions and a satisfactory indoor climate. The hypothesis of this project is that such roof window products can be developed if amongst others the optimal balance between the heat loss coefficient, the light transmittance and the solar energy transmittance is reconsidered for use in low energy buildings. Furthermore, the buildings’ geometry, use and orientation as well as the dynamical outdoor light and weather conditions must be taken into account in the analyses.

The project will include work with detailed models for determining the coupled energy and daylight performance of different roof window concepts in low energy European single family houses and school buildings. It is expected that the analyses will lead to new knowledge about the future demands and possibilities, which will make up a basis for the development of new types of roof window products for use in fossil free low energy buildings.

Adaptive Façade Design for the Daylighting Performance

by Jieun Kim, University of Nottingham, United Kingdom

The objective of this research is to develop an innovative façade design strategy that comes from the development of digital technology and dynamic daylight performance measuring methods. Thus, the various parameters are studied through the computational process of Cellular Automata to generate the several alternative opening patterns on the building façade. The each CA design values were tested under static and dynamic sky condition to analyze the quality and quantity of daylight and its performance throughout the whole year. The results were compared to find the optimum alternative designs in terms of the daylighting design criteria, which were researched from building code, standard and design guidelines for the office building.

Finally, the research of an adaptive façade design strategy was concluded with the results from the above hybridization of generative and performative design methodology. This study discovers the architectural design approach from the CA and it will make not only progress in building façade aesthetics, but also human comfort with building sustainability.

Design Methodology and Criteria for Daylight and Thermal Comfort in Nearly Zero-energy Commercial Buildings in Nordic Climate

by Line Karlsen, Aalborg University, Denmark and Oslo and Akershus University College of Applied Science, Norway

During the last decade there has been a trend to design office buildings with large glazed areas in the façade and/ or with a compact building body to decrease the ratio of façade on floor area, which commonly results in deep room layouts. Even for low energy buildings it is seen examples of architecture with locally large areas of glass even though the building envelope consists of a low fraction of glass on an average basis. Many of these buildings experience indoor environmental problems like overheating and glary conditions in the perimeter zones and lack of daylight in the core of the building in addition to end up with a high energy demand for both heating and cooling. The question have arisen if the underlying reason for these climatic and energy related problems may be addressed erroneous design methods used in the project planning phase and maybe too simplified evaluations of indoor environment and energy demands? Maybe other solutions e.g. for the façade and room layout would have been chosen if the risk of these problems were discovered in the design phase?

This project considers the integrated aspects of thermal comfort, daylighting and energy use of commercial buildings. The objective of the work is to develop an improved methodology for design of commercial buildings in Nordic climate where the aim is a balanced approach to fulfillment of future requirements for energy use, thermal comfort and daylighting.

Supervisors: Per Heiselberg, Aalborg University, Ida Bryn, Oslo and Akershus University College of Applied Science

Modeling View Directions – 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.

Supervisor Marilyne Andersen, EPFL

A Dynamic Computational Model to Evaluate Non-visual Effects of Light on Human Health in Buildings

by María Ámundadóttir, Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland

Lighting is one of the most significant factors in the built environment that affect human health and wellbeing. In addition to stimulating visual responses, light induces a range of non-visual responses in humans including synchronizing circadian rhythms and directly alerting the brain. These effects are primarily mediated via a novel photoreceptor that contains the photopigment melanopsin. The spectral sensitivity of melanopsin is shifted towards the blue part of the spectrum compared to rod and cone photoreceptors used for vision. Therefore, making the most of the available daylight, which is naturally rich in the blue part of the spectrum, is a promising approach and might play a large role in lighting recommendations for health.

Lighting simulation software tools are designed to predict and analyze the  dynamically changing nature of functions that take place in architectural settings influenced by occupants’ behavior and the outside environment. Because non-visual responses adapt to changes in light intensity and spectral composition over much longer time periods than visual responses, they must be evaluated based on dynamic threshold values with regard to intensity, spectrum, duration, history and timing of light exposure. However, existing lighting design methods, used to assess visual performance and comfort, are based on static threshold values, and thus cannot be directly applied to evaluate non-visual responses.

The goal of this thesis is to develop a computer-based lighting simulation framework able to predict direct non-visual responses to light and to validate novel guidelines that can inform designers about how lighting might affect human nonvisual responses in the built environment. One of the main challenges to be addressed is the dynamic interaction between daylighting, occupants’ behavior and human nonvisual responses to light.

Determination and Characterization of Indicators that Intervene in an Integrated System of Daylighting and Sun Protection. Optimization Applied to Hollow Existing Facades.

by Marlix Perez Gonzalez, ABIO – UPM Research Group, Spain

The thesis is about strategies to improve lighting and heating conditions of the room. One strategy investigated is the Fragmented Light Shelf, which is a system that can be easily incorporated into the window. The study arises from the software simulation and monitoring in 1:10 scale model of some sun protection options a light shelf. The results show that the system prove to work as sun protection, while improving natural lighting at certain times of day. However, it is necessary to optimize the performance and extend the scope to other Spanish cities with different climatic conditions to those of Madrid.

Robust Control Systems for Lighting Retrofit: Technical and Non-technical Issues

by Niko Gentile, Energy and Building Design Division, Lund University, Sweden

An efficient lighting control system for non residential buildings should take advantage of the natural light available in order to save energy. This entails some technological challenges and user related issue, while today, the assessment of lighting energy consumption is mainly based on the technical features and the occupant’s interaction is often neglected.

This project will demonstrate the energy saving potential of control systems in laboratory as well as in field studies. It will also provide a review of technical and non-technical issues related to control systems as well as an inventory of existing systems and clarification about meaningful and efficient technique for lighting control (regarding sensors, IT, optics, etc.) and anticipated problems and solutions, with a focus on the work environment. Overall, the project will support the development of highly efficient and robust, user-friendly, maintenance-free control systems compatible with the latest IT technology and with LED retrofit.

Supervisor: Marie-Claude Dubois

Towards Design of Daylighting Conditions in Architecture: Climate-based Luminous and Thermal Impact Analysis

by Paula Esquivias, University of Seville, Spain.

Daylight is one of the most relevant parameters involving the interior environmental conditions of the spaces of a building. Throughout the History of the Architecture there are a lot of examples of singular buildings where daylight qualifies the interior space. Until the expansion and popularization of artificial lighting, the interior lighting environment was determined by daylighting conditions, conditioned by the construction techniques of the envelope, the local climatic conditions and the surrounded environment were the building is placed. After the normalization of the use of artificial lighting, daylighting and its techniques were relegated to a very second place during the design stage of new buildings.

The development of building science led to the development of calculation algorithms to guarantee certain minimum requirements about every aspect regarding buildings. This concern to have better scientific knowledge also was reflected in the field of luminous conditioning. In this context, the amount of light entering into a room began to be quantified, some concepts like Daylight Factor were developed and the luminous distribution of the sky vault for different sky conditions were mathematically formulated. The development of the Climate-based Daylight Modelling, and its metrics, allowed us to know hourly (or sub-hourly) values of global illuminances at each point of the workplane for a specific annual time range.

On the other hand, after the 1973 oil crisis and the climate change awareness some strategies, directives, protocols and agreements have been developed to decrease the energy consumption and the CO₂ emissions to the atmosphere, including buildings’ energy consumption, based on hourly energy simulation results. The Solar radiation with such an enormous impact in thermal and luminous conditioning is usually treated separately depending on the analysis –thermal or luminous –that is intended. An Integral Approach is fundamental to give an efficient passive strategy and to design interior environment from de early building design stages.

The main objective of this thesis is to promote a passive architectural design considering the amount of natural light in equilibrium with thermal loads through the study and analysis of the different parameters involved in natural lighting conditions by combining the calculation of dynamic daylighting metrics with load calculation heat due to direct sunlight.

To achieve this, it goes over those components involved in daylighting conditions of an architectural space analysing their hourly luminous and thermal impact in terms of illuminances and kW due to solar heat gains. This thesis proposes a change in the statistical analysis of the hourly illuminance values to obtain the CBDM based on an hourly workplane analysis and based on the daytime hours. Distribution of hourly illuminances and solar heat gains on the workplane qualify every model performance, meanwhile temporal maps of useful illuminances and solar heat gains quantify them.

Finally, a small experiment is performed to verify that the luminous and thermal characterization of every daylight element can be used as daylighting and sunlighting design and control tool for new buildings, and as daylighting and sunlighting knowledge tool for existing buildings.

This experiment assumes that interior daylighting is the result of the sum of the individual impact of every element involved in the availability, entering or distribution of the visible and infrared solar radiation in a space. To refute this hypothesis a simulation of a relatively simple architectural work is performed where its daylighting is of high relevance and it is compared with the result obtained by the contribution of every daylight element of this architecture to the daylight and thermal interior environment. The refutation of this hypothesis will allow for the use the luminous and thermal characterization as effective tools for daylighting design and control applicable to new architectural projects and to understand the daylight and sunlight environment of complex spaces, such as Architectural Heritage.

Impact of Daylight on the Use of Lighting Controls

by Pimkamol  Maleetipwan-Mattsson, Lund University, Sweden

Daylight may contribute to energy savings due to that it may eliminate the use of electric lighting. The study was conducted in 18 single-occupant offices to examine the occupants’ use of different kinds of lighting controls in relation to daylight availability. The 3 offices were equipped with the same kind of lighting control. In total, the following 6 different kinds of lighting controls were studied throughout the period of one year.

To examine the use of each kind of lighting control, switch-on time and occupied time per day were measured in each office, respectively and then the averages for each month were calculated in hours. Further, ratio of the average occupied time to the average switch-on time was calculated to examine how the occupant used electric lighting from ceiling luminaire.  Preliminary findings pointed to the actual impact of daylight on the use of lighting controls. For every kind of lighting control, electric lighting from the luminaires was used less during spring and summer (March-September) than autumn and winter (October-February). Further, it was found from independent sample t-tests that there were significant differences in the use of electric lighting by using the manual on/off, manual dimming, and automatic dimming controls.

Modelling and Simulation of Virtual Natural Lighting Solutions in Buildings

by Rizki Mangkuto, Eindhoven University of Technology, the Netherlands

Natural light entrance in buildings has a limited availability in practice, particularly in space and time. Examples of this situation can be found, among others, in cubicle workspaces in open-plan offices, operating rooms in hospitals, and control rooms in industrial plants. In such situations, the concept of Virtual Natural Lighting Solutions (VNLS), which are systems that can artificially provide natural lighting as well as a realistic outside view, can be promising. The benefit of installing VNLS in a building is the possibility to use more floor area that currently has very limited or no access to daylight, with the additional possibility to control the light and view quality.

This thesis aims to predict the impact of various VNLS applications on lighting performance and visual comfort in buildings, by means of computational modelling and simulation. The development process is based on measurements of a first and a second generation VNLS prototypes, followed by computational modelling of future VNLS, which involves arrays of small light sources with various tilt angles to deliver the light in various direction. Overall, the main contribution of this thesis is demonstrating the application of computational modelling and building performance simulation in providing multiple design concepts to improve the objective performance of VNLS.

Dynamic Perceptual Effects of Daylight in Architectural Space

by Siobhan Rockcastle, Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland

Daylight offers both functional and aesthetic value to architecture, providing natural and energy-efficient illumination for interior tasks and infusing interior space with light, shadow, and texture.  Unlike artificial light sources, which can be adjusted to meet a desired luminous effect regardless of latitude, climate, or time of day; daylight is sensitive to a number of dynamic conditions. These variable conditions result in a highly dynamic source of illumination and perceptual phenomena.  While many architects have expressed the importance of these phenomenological effects on our perception of space we are left with disproportionally few, if any, daylight design metrics that can evaluate the positive impacts of luminous variability within the visual field.

While ask-based illumination metrics and visual comfort metrics have gained predominance within the last several decades, perceptual performance indicators such as contrast and variability, are traditionally defined as qualitative design factors and quantitative methods to explore their impact or relevance have been limited.  Although subjective in nature, the visual perception of space is central to architectural design and criteria for its performance must be considered alongside illumination and comfort metrics to develop a more holistic evaluation of daylight in architecture.  This research will propose a new family of metrics for quantifying the dynamic performance of contrast and luminance-based visual effects in architectural space.