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The prediction of daylight availability in indoor environments is nowadays an extremely relevant topic in the design practice for many reasons: it affects the design of the electric lighting system and therefore the calculation of the related energy consumption; it also has an impact on evaluation of comfort. Dynamic daylight simulations are a helpful tool to predict daylight availability in indoor environments and consequently to evaluate the possible reduction in energy consumptions. However, there are different software packages that perform dynamic daylight simulations and they use different engines and calculation methods which may be a source of differences in the results. Moreover this type of analysis requires a weather data file of the building's location to be performed. Since there are many of them available, which are developed from historical sets of weather measurements using different methods, the use of one or another can affect the simulations' results. Therefore in this paper an example of the impact on dynamic daylight simulations' results of different weather data files (IWEC, Meteonorm, TRY and Satel- Light) and different software (Daysim and 3ds Max Design®) will be reported.

It is by now accepted that light has significant effects on people well-being in terms of both visual and non-visual comfort. According to the Hue Heat Hypothesis, Correlated Colour Temperature can affect people thermal perception: a cool light would determine a cool sensation and a warm light a warmth sensation. Despite several studies investigated this issue, published results are conflicting. The paper shows outcomes of laboratory surveys that are in good agreement with the HHH. Moreover, it presents results of dynamic daylight simulations aiming at studying the way design strategies, implementing the HHH, modify indoor luminous environment and energy consumptions due to lighting.

The application of “shiftable” or “modulable” load (i.e. washing machine, dishwasher, etc.) in a Smart Grid, can provide energy saving or modify the power flows in the grid, allowing a reduction of the electrical power peak. This paper explores the possibility to modulate the indoor artificial lighting to support this reduction. The study examines the impact of two different measures of power shaving. On the one hand, the change of Correlated Colour Temperature of the light source, and, on the other hand, the dimming of its luminous flux. The possibility to merge the above-mentioned technical solutions is also analyzed. Based on these strategies, several daily schedules of lighting management are defined, and the corresponding energy saving during some critical time slots are assessed. Results show that in all cases, it is possible to achieve a significant reduction of the absorbed power and a consequent increment of energy savings (up to 59%) also in specific time ranges. Furthermore, considering the application of a Daylight-linked control system, it was observed that power regulation associated with the exploitation of the daylight represents itself a way to dynamically reduce the electric loads on the grid.

This paper proposes a study about the feasibility to modulate the indoor artificial lighting, taking into account both achievable energy savings and comfort conditions, in order to reduce lighting electric loads. In particular, it focuses on the possibility, on one hand, to decrease the luminous flux and, on the other hand, to change the Correlated Colour Temperature (CCT), in order to decrease the absorbed power. Moreover, the impact of daylight-linked control systems was considered. Finally, the possibility to combine the different technical solutions was analysed. The paper proposes the definition of daily scheduling referred to lighting energy management, in order to modulate the maximum load value, maintaining a minimum during the rest of the time for an office end use.

Nowadays, there is an in-depth debate about the suitability of daylight saving time. The shift of one hour during summer time allows a better use of daylighting reducing energy consumptions. However, the impact of daylight saving time on the human health has not been quantified in most of the scenarios. The aim of this study is to determine the impact of daylight saving time on the health of occupants (by calculating Circadian Stimulus Autonomy) and on the energy consumptions for lighting (by calculating Daylight Autonomy) in office buildings. A standard office is analyzed in eleven representative locations of Europe and for three different time schedules: with daylight saving time, with continuous winter time and with continuous summer time. Despite restricted to a specific case study, results provide elements useful to evaluate pros and cons in maintaining daylight saving time, confirming that they are strongly dependent on the geographical position and on the local luminous climate. It was demonstrated that, abolishing daylight saving time, maintaining the local time all the year (winter time), would determine a reduction of Daylight Autonomy generally lower than 6% and that this decrease would be more consistent for cities characterized by higher latitude. At the same time an increase of Circadian Stimulus Autonomy values would be obtained, more consistent for northern cities (maximum observed increment 16%). On the other hand, applying the one-hour shift for the entire year (summer time) would not determine benefits in terms of energy savings nor of impact on circadian system.

The goal of the paper is to analyse the daylighting design criteria in ancient Roman domus, by using as case study a famous ancient Roman building: the villa of the Mysteries in Pompeii. At this purpose the work is divided in two sections: a typological analysis of the roman houses, aiming at understanding the link between the ancient building criteria and the daylight harvesting ones; a dynamic simulation of the daylight conditions inside the Villa of the Mysteries. In this regard, to assess the indoor daylight availability an ad-hoc methodology, based on the proposal of a new set of performance metrics (the Characteristic Daylight Illuminance -CDI-; the minimum CDI - CDImin-; the spatial CDI -sCDI-) is introduced in order to process simulation results. Results demonstrate that in the past there was a strong correlation between building criteria and daylighting ones: the choices about the dimensions of the windows and the use of static shading systems (porches and peristyles) were wise and reasoned. Moreover, there was a correspondence between daylighting criteria and the functions of the spaces: the more prestigious a room was, the more daylight entrance was permitted. Daylight levels were generally higher in representative spaces like atria, triclinia and tablina, with CDImin values generally comprised between 200 lx and 500 lx, and lower in cubicula and service/working spaces, with CDImin values generally comprised between 0 lx and 100 lx. The obtained results can be useful to design the modern electric lighting system in the villa. Moreover, the proposed analysis methodology can be easily exported to other applications (both ancient and modern buildings). Further studies should apply the same methodology to other case studies to verify if the outcomes of the research are generalizable. Fil: Monteoliva, Juan Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Ambiente, Hábitat y Energía; Argentina Fil: Bellia, Laura. Università degli Studi di Napoli Federico II; Italia Fil: Fragliasso, Francesca. Università degli Studi di Napoli Federico II; Italia Fil: Pattini, Andrea Elvira. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Ambiente, Hábitat y Energía; Argentina

This paper presents an experiment on the effect of light on the perception of paintings. The experiment was performed in a test-room where a typical museum exhibition set-up was simulated. Two different paintings were shown to 44 participants, under different light scenes obtained by using tuneable LED (Light Emitting Diode) wallwashers. To set the light scenes, the following parameters were modified: correlated colour temperature of the lighting, illuminance on the painting and the colour of the background wall. Participants answered a questionnaire to assess the perception of the paintings’ colours, the lighting conditions and the pleasantness of the exhibition set-up. The results demonstrated that illuminance is the parameter mainly affecting perception, for both paintings. However, correlated colour temperature and wall colour, as well as the combination of the three different considered parameters, can more or less influence perception depending on the chromatic composition of the painting.

Evaluating indoor daylight availability is extremely important in order to define the characteristics of an environment in terms of visual comfort and energy performances of lighting systems. The criticism of the static calculation approach based on Daylight Factor led to the development of the Climate Based Daylight Modeling (CBDM) one. Dynamic simulations are performed thanks to the use of specific software and the choice of a calculation tool or another could provide different output results. Therefore the aim of this paper is to compare results of dynamic daylight simulations carried out with two different software, Daysim and 3ds Max Design® and referred to a simple office located in 4 different cities and exposed according to the 4 main orientations. It demonstrates that differences in results are more or less significant depending on several factors: outdoor daylight conditions, window’s orientation and considered internal calculation point.

This paper is the second step of a research project aimed at investigating the impact of the use of different weather data files on daylight simulations’ results. Simulations were carried out for a simple standalone office using three weather files (IWEC, Meteonorm and Satel-Light) for two European locations (Copenhagen and Rome); moreover the office’s exposure was changed according to the four main orientations (North, East, South and West). Results were analyzed both in terms of Annual and Monthly Light Exposures, dynamic daylight performance metrics (DA, DAcon, UDI) and sunlight’s incidence. It was demonstrated that differences between the results obtained with the different weather files are more significant considering Annual and Monthly Light Exposures (highest value 20%), whereas they decrease when analyzing illuminances with a statistical approach (DA, DAcon, UDI). The analysis of sunlight’s incidence also determined similar results using the three weather data files and the maximum difference is 5% independently from the orientation.

The research presented in this paper reports an analysis of daylight in three offices with different exposures and characteristics located in Naples (Italy). The goal was to fully investigate daylight characteristics, also considering the circadian impact of daylight entering these offices, with the hope to develop guidelines to better assess daylight quality in built environments. One of the main findings of this research is that the spectral distributions and CCTs of the light reaching the eye of a person seated at the desk in these offices are similar irrespective of the offices' different characteristics (dimensions, surfaces' spectral reflectances, external obstructions, etc.) and different sky's conditions. Moreover it was found that eye level irradiances and their circadian impact is similar to those of D50 and D55 CIE standard illuminants. The same measurements will be carried out in other seasons and a comparison between measured values and software simulated ones is also planned.

Light induces not only visual responses but also non-visual effects, indeed it affects performance, mood, attention and influences the synchronization of the biological clock. Duration, timing, intensity and the spectral power distribution of the light that reaches the eyes can have influence on human circadian rhythm and consequently on health. Given the important impact of the non-visual responses on people wellbeing, developing a model that allows lighting designers to predict them is a fundamental goal. In this paper a case study is reported: a series of measurements were carried out in a University classroom in order to study daylight and electric light characteristics and also their impact on the human circadian system by calculating melatonin suppression. The results obtained show that not only the intensity but also the SPD of the light received by the eyes plays a significant role on circadian response and the spectral characteristics of internal and external surfaces influence the SPD and therefore the CCT of the light that hits the eyes. Although the working behavior of the human circadian system is not completely understood, the results obtained give the designers new points of view to better evaluate lighting quality and its implications in indoor environments.

Recent availability of video-cameras with CCD-type sensors (charge coupled device) has proved to be particularly stimulating for all those applications requiring photometric measurements, above all for the measurement of luminance values related to the physical and technical qualities of a built environment. This method allows the instantaneous capture of an image, thus enabling collection of luminance values relating to the points of measurement; this in turn leads to the evaluation of luminance distribution and lighting levels of the surfaces that make up the environment. Setting up this system requires the following basic configuration: a photopic filter V ( λ ), an optic interface, a computer equipped with an appropriate card for the capture and digitalisation of the acquired image (the “frame grabber”) and, finally, suitable software for the processing of collected data. In this article a detailed description of this acquisition system is reported, and subsequently a report on the procedure adopted for its calibration so as to enable the capture of relevant photometric values. Final analysis and validation of results are carried out by means of field test. A case study of CCD photometer application has been then performed using a basic software tool autonomously developed to evaluate indoor lighting level; the luminance map of a diffuse light source has been used as “input” data for the developed software, and the “output” data, i.e. illumination levels, have been then compared with measured values.

Taking into account the functional relationship between visible radiation and its effects on human circadian system, an optical sensor system has been developed with capability of bio-miming human visual and non-visual stimuli by means of a simultaneous monitoring of particular radiation frequencies for indoor lighting. This optical sensor system is made of 5 photodiodes equipped with passband optical filters, based on sputtered AlN-Ag interferential layers and having the maximum transmission peak positioned at the response wavelengths of the human photoreceptors (cones, rods and ganglion cells). When exposed to different light sources this photosensor system is able to qualify the responses of the five photoreceptors, useful to evaluate lighting quality both as visual and non-visual effects are concerned.