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Immersive virtual reality allows showing people virtual environments with high levels of presence, realism and “feeling of being”, as if they were in the real world. To reach this goal, virtual environments have to provoke perceptions that people experience in physical ones and ensure correct light distributions. A way to evaluate the virtual reality accuracy in reproducing real spaces is to perform experiments with human subjects. In this paper, the role of subjective assessments in lighting research using virtual reality is investigated. Review highlights that subjective assessments play an essential role in using virtual reality for lighting studies, being used to: i) compare virtual and physical environments, ii) compare different lighting scenarios and iii) investigate users’ lighting preferences.

Additive manufacturing has seen a growing interest in the construction industry in the last few years. Along with the possibility of using plastics, cement, clay, mixtures, and so many other materials, the opportunities offered by such technologies mainly rely on the free-shaping of complex geometries and the high customizability of the products. Nowadays, the aim of integrating additive manufacturing processes in the construction stages is to reduce waste materials and reduce the overall environmental impact. This review summarizes the current state-of-art of additive manufacturing, mainly 3D printing, applied to architecture, in current research activities, and actual built projects. The aim is to delineate a comprehensive scenario of its possible applications and current limitations, finally suggesting the opportunities for future investigations.

Virtual reality has made a great progress over the past recent years both in recreational and professional fields. However, several factors can affect the capability of the virtual reality from the realism point of view. Luminance and colour of the stimuli could be considered as the main parameters which participate in this challenge. On the other hand, the complex way that virtual reality software such as the Unreal game engine manipulate the virtual scene before to be sent to the Head Mounted Display, can affect the desired goal. This review tries to have a general overview reached so far on the characterisation done in head mounted displays so as to evaluate the quantity and the quality of the light reaching users’ eyes. Further, a discussion on the open issues in the field is provided as well.

The consumption of energy for lighting in buildings depends very much on the way people interact with the build environment. In this study the following building types were studied, office, school, university, commercial and industry buildings. For each building type typical user groups were identified. Then, Personas have been created for each group. As opposed to describing users with numbers and statistics, a single Persona reflects a group and is presented with a narrative. The Persona has a name, a family and living conditions that are representative for the group, also her/his values and interests are not uncommon. The Personas “typical day” includes a time schedule typical for the group. Visual conditions are common for the group, but some specific challenges connected to the visual conditions that may occur in the group are also mentioned. Personas were created using one of the three methods: interview at the working or learning place, workshop at the working place, and internet survey which was used in the time of pandemic lock-down. Those methods are described in the chapter 2 Methodology and evaluated based on the authors experience, chapter 9 Conclusions. Chapters 3-7 presents Personas for the offices, schools, university buildings, commercial buildings, and industry buildings. In the chapter 8 Home office personas, student and professional, are presented. The report ends with the description of energy consumption calculation that applies Lumen method which is based on the use of a Coefficient of Utilization (CU). CU computes the fraction of lamp lumens that directly reach the workplane and the fraction from interreflections. The boundary conditions of use of the respective buildings, based on the results from literature review and interviews with users, are also presented, table 2.

The report starts with the introduction, chapter 1, where the main objective of the work is formulated, namely, to examine how the public buildings are used regarding lighting; both daylight and electric light is considered. In the chapter 2 a review of codes and requirements has been done. It starts with a discussion about general aspects of codes (subchapter 2.1) and presentation of international standards CEN and ISO (2.2) and follows with description of CIE reports and other internationally recognized guidance books (2.3). Then national recommendations are also presented (2.4). Finally, the impact of codes on architectural design is elaborated based on the interviews with architectural offices (2.5). Chapter 3 presents the studies of buildings usage based on the extensive literature review. The following public building types are included: offices, schools, university buildings, hospitals, commercial buildings, industry buildings and libraries. Chapter 4 focuses on occupancy and use of lighting systems. It starts with a discussion of the occupancy simulations and their usefulness in the current project context. Then, it follows with occupancy registration and use of lighting in chosen buildings located in different European countries. It includes registration in an office building in Italy, a primary school building in Norway, a university building in Poland and one industry building, also in Poland. The research method used in registration consisted of simultaneous registration of occupancy and use of (day)lighting with the help of a self-report diary, and light-technical measurements. The diary registration and the measurements were performed at the same day, in most cases in February/March 2020, that is just before the pandemic lock-down in Europe. Then, the use of electric light had been compared with the occupancy and (day)light level indoors/outdoors. The registration was carried out in each of the buildings for one day only. As such, it should be considered a form of stick sample to check the findings from the literature study presented in the chapter 3. Computer simulations were done for school and university buildings to estimate the light level during the whole year. The registration confirms a pattern of occupants’ behaviour found in literature. In general, occupants consider the visual environment at the workplace when they enter or leave the room. It happens mainly at the beginning (adjustment of blinds and switching on the electric light) and at the end of the working day (switching of the light). The use of lighting follows occupancy pattern, and not daylight level outdoors, something that indicates significant potential for energy saving. Chapter 5 Conclusions conveys general results regarding codes and more specific results regarding use of the different building types.

This report presents tools for post-occupancy evaluation (POE) to evaluate indoor lighting of commissioned projects (‘case studies’) under a common framework. In this report, POE includes technical environmental assessment (TEA) and observer-based environmental assessment (OBEA). The framework proposed in this report evaluates four key aspects of the case study: 1. Energy use (electrical lighting systems), 2. Visual effects (Indoor lighting environment /photometry) 3. Non-visual effects (circadian potential), and 4. The user (subjective/surveys and observations) The report targets industry professionals, building designers, lighting designers, building managers, researchers and/or owners wishing to evaluate projects where lighting is supplied by a combination of electrical lighting, daylighting systems (e.g., fenestrations) and assisted technologies (e.g., smart sensors). The framework in this report makes available methods and procedures related to the evaluation of integrated lighting performance in residential and non-residential buildings and its impact on users, and it summarises and categorize methods and procedures in an accessible and industry-oriented language. The content of this document is based on methods and procedures used by participating experts in IEA SHC Task 61 for monitoring twenty-five worldwide integrated daylighting and electric lighting case studies. Since integrated lighting projects are different in type and scopes, the methods and procedures included in the framework do not follow a rigid protocol. Practitioners should use the framework to define the scope of POE monitoring in terms of the aims of the project, context, and resources available. The document is thus a toolbox for planning and executing the monitoring of their integrated lighting projects.

Measures for the reduction of electric energy loads for lighting have predominantly focussed on increasing the efficiency of lighting systems. This efficiency has now reached levels unthinkable a few decades ago. However, a focus on mere efficiency is physically limiting, and does not necessarily ensure that the anticipated energy savings actually materialize. There are technical and non-technical reasons because of which effective integration of lighting solutions and their controls, and thus a reduction in energy use, does not happen. This literature review aims to assess the energy saving potential of integrated daylight and electric lighting design and controls, especially with respect to user preferences and behaviour. It does so by collecting available scientific knowledge and experience on daylighting, electric lighting, and related control systems, as well as on effective strategies for their integration. Based on this knowledge, the review suggests design processes, innovative design strategies and design solutions which – if implemented appropriately – could improve user comfort, health, well-being and productivity, while saving energy as well as the operation and maintenance of lighting systems. The review highlights also regulatory, technical, and design challenges hindering energy savings. Potential energy savings are reported from the retrieved studies. However, these savings derived from separate studies are dependent on their specific contexts, which lowers the ecological validity of the findings. Studies on strategies based on behavioural interventions, like information, feedback, and social norms, did not report energy saving performance. This is an interesting conclusion, since the papers indicate high potentials that deserve further exploration. Quantifying potential savings is fundamental to fostering large scale adoption of user-driven strategies, since this would allow at least a rough estimation of returns for the investors. However, such quantification requires that studies are designed with an inter-disciplinary approach. The literature also shows that strategies, where there is more communication between façade and lighting designers, are more successful in integrated design, which calls for more communication between stakeholders in future building processes.

This report presents lessons learned from twenty-five worldwide real-life case studies implementing the integration of daylighting and electric lighting. The case studies were monitored with respect to energy use for lighting, visual performance, non-visual performance, and users’ satisfaction. The monitoring is largely based on field measurements, but it is also complemented with simulations and calculations where needed. The report is divided in two parts. The first part provides an overview of the case studies and the overall lessons learned. The second part provides factsheets for each of the case studies; the factsheets include details on the monitoring, results, and specific lessons learned. Based on the lessons learned from the case studies, this report concludes that: • The energy demand for lighting is drastically reduced thanks to the combined effect of more efficient light sources, advances in controls, and raised awareness in the integration of daylighting and electric lighting. • Integrative lighting is currently driving the innovation in lighting technology and wider implementation is expected as knowledge in the field of non-visual requirements for lighting expands. • However, the current integration of the integrative lighting concept with daylighting in practice is limited, which may result in significant energy rebound (increases). • Daylighting integration is of utmost importance for achieving quality beyond energy savings. • Integrated daylighting and electric lighting design is facing new challenges: questions connected with comfort and health are yet to be answered.