Practicality and Performance of Daylight Trough in The Tropics: A Case Study

In office buildings, an efficient design of windows and using light shelves as a passive design strategy significantly influence the thermal and visual comfort of occupants while enhancing the productivity and health of users. This study proposes a multi-objective optimization for the optimal design of windows and light shelves in office buildings to improve occupants' comfort. Initially, a parametric model was developed using Grasshopper parametric software. Afterward, the Honeybee energy and daylight plugin was employed for simulating thermal and visual conditions, and finally, multi-objective optimization was conducted with the Octopus plugin. This plugin can determine the best solution as a compromise decision for maximizing occupants' comfort. In this paper, an office building in Tehran has been chosen as a case study. The decision variables are window-to-wall ratio (WWR), shading control strategy, viewpoint, the transmission of glass, light shelf length, and light shelf height. The objective functions of the study are the annual average Predicted Percentage of Dissatisfied (PPD) and the annual average Discomfort Glare Probability (DGP). According to the results, the proposed optimization model leads to an 18.5–70.1% and 9.3–57.1% reduction in DGP and PPD indexes, respectively. The study findings provide practical and useful instruction for architects to select optimal specifications of windows and light shelves to develop occupants' thermal and visual comfort in office buildings.

Daylight can be considered as one of the most important principles of sustainable architecture. It is unfortunate that this is neglected by designers in Tehran, a city that benefits from a significant amount of daylight and many clear sunny days during the year. Using a daylight controller system increases space natural light quality and decreases building lighting consumption by 60%. It also affects building thermal behavior, because most of them operate as shading. The light shelf is one of the passive systems for controlling daylight, mostly used with shading and installed in the upper half of the windows above eye level. The influence of light shelf parameters, such as its dimensions, shelf rotation angle and orientation on daylight efficiency and visual comfort in educational spaces is investigated in this article. Daylight simulation software and annual analysis based on climate information during space occupation hours were used. The results show that light shelf dimensions, as well as different orientations, especially in southern part, are influential in the distribution of natural light and visual comfort. At the southern orientation, increased light shelf dimensions result in an increase of the area of the work plane with suitable daylight levels by 2%–40% and a significant decrease in disturbing and intolerable glare hours.

Determining multidimensional diffuse reflection effects in city tunnel lighting environment

Improvement of energy efficiency in buildings is the goal of many activities around the world. In recent years a need to increase the number of buildings, which not only fulfil the minimum energy performance requirements, but have very low energy consumption and are environmentally friendly has been recognised. In this paper the issues of electric lighting quality in educational buildings, focused on the analysis of lighting energy efficiency are presented. A brief characteristic of the selected educational building and requirements for the assessment were presented. The lighting conditions in selected interiors of the building and the lighting energy efficiency in the whole building were evaluated. To demonstrate the opportunity to improve lighting conditions and energy efficiency, four solutions for each selected interior were proposed. New fluorescent and LED lighting solutions were compared in detail. The comparison between the existing lighting and new solutions was conducted either. The lighting in evaluated building was not energy efficient and what worse, the lighting conditions in many interiors were much below the requirements. Introducing new lighting solutions should improve the quality of luminous environment in interiors and reduce substantially the lighting power installed as well as the energy use in the building.

As lighting energy consumption increases, various studies are carried out to solve such a problem. As a solution to the problem, a variety of studies are conducted since the performance of light-shelf using external natural light is excellent. The light-shelf is divided into external, internal and mixed type light shelves, and also it is divided into single light shelf and double light-shelf according to reflector's installation type. Preceding studies on light shelves are mostly simulation studies. In this regard, this study aimed to conduct an experiment research of double light-shelf, and the study results are as follows: 1) When a double light-shelf is applied, average illuminance increases compared with a single light-shelf. 2) When an internal double light-shelf is applied, uniformity factor declines compared with a single light-shelf, and this is a factor to consider in installing a light-shelf. 3) In case of the internal double light-shelf selected in this study, when separation distance diminishes, uniformity factor improves. Also, when separation distance is 100mm, indoor illuminance distribution is high, which is advantageous to lighting energy reduction. Therefore, proper separation distance of an internal double light- shelf is 100mm on the summer solstice.

Building-integrated photovoltaics (BIPV) show potential as a means of efficient solar energy harvesting. This paper introduces a multi-objective framework for finding the optimized design of parametrically modeled photovoltaics integrated light shelf systems to maximize their benefits to the indoor environment and users. Since the geometric design of traditional shading devices is restricted to rectangular-shaped panels, we aim to attain a clearer perception of the potential advantages of employing panels with novel design alternatives. First, we developed parametric models of internal and external light shelves; each consisted of either a surface with a curved section or a 4-point planar surface. Next, the assessment of daylight and energy operation along with occupants' thermal and visual comfort was carried out using the environmental plugins of Honeybee and Ladybug. Furthermore, to decrease the required lighting energy and upgrade users' visual satisfaction by providing favorable illuminance levels required for a specific task, we divided the classroom into alterable lighting zones. Lastly, the optimization process was performed via the Octopus plugin for Grasshopper, and optimal solutions were identified. Based on the numerical results of the yearly simulations, we gained noticeable energy-saving up to 29% while improving occupants' thermal and visual comfort.

The Moroccan manufacturing sector consumes 24% of the country’s total energy production. Morocco is dealing with energy challenges related to its growing energy consumption, which has made energy efficiency a national priority. In this study, we construct a model that includes mimetic pressure and financial slack as drivers to reduce the intensity of risk aversion regarding electrical energy efficiency practices within companies. Our research model was empirically examined using survey data gathered from 193 manufacturing companies located in four Moroccan regions. Results show that risk aversion is negatively related to energy efficiency practices. Both mimetic pressure and financial slack are positively related to energy efficiency practices. Both mimetic pressure and financial slack reduce risk aversion. Mimetic pressure dampens the negative relationship between risk aversion and energy efficiency practices, while financial slack does not dampen the negative relationship between risk aversion and energy efficiency practices. This study shows the importance of mimetic pressure in reducing risk aversion regarding energy efficiency practices. Therefore, policymakers should publicize in the media companies that have gained from the adoption of energy efficiency practices and establish an award system of best energy efficiency practices in each industry. This study is an extension of the previous literature since we found that financial slack decreases the level of risk aversion, but this does not always translate into energy efficiency practices, as the previous literature assumes.

Population aging is an inevitable universal demographic process. Aging exposes people to physical, sensory, and psychological changes that often lead to health declination and cause dependency. In developed countries, elder care facilities emerged widely to ensure the aging perception of home as a safe and comfortable environment when family members are not around to assist. The elderly spend most of their time indoors; thus, indoor lighting design and visual comfort are vital for their safety. Comfort contributes to the well-being of the elderly as a part of the social sustainability context. The aim of this research is to set visual comfort design guidelines for elder care facilities in developing countries. To achieve this, a methodical review was carried out of published literature on lighting, environmental gerontology, and enhancement of visual comfort for the elderly. Then, an analysis of the environmental gerontology approach application in elderly built environments was carried out. Finally, a summarization of preliminary guidelines for visual comfort that can be applied in developing countries to form aging-friendly space was made. The findings establish recommended guidelines and proposed solutions that would improve the daylighting environment in elder care facilities from the gerontology perspective. This research highlights the important role of environmental gerontology in creating an age-friendly environment that fulfills the physical and psychological needs of the elderly, especially in daylighting aspects, thus promoting social sustainability.

Multi-objective parametric optimization of the composite external shading for the classroom based on lighting, energy consumption, and visual comfort

As socio-economic advancements raise living standards, the demand for comfortable indoor environments has increased, highlighting the important role of daylighting in enhancing thermal and visual comfort. Shadings, as well-known building facade elements, encourage efficient energy usage, can offer multiple health benefits to users and help create more efficient working spaces by solving potential issues of glare and heat through daylight control. To solve multi-objective design challenges of shadings, the Genetic Algorithm (GA) emerges as a contemporary solution. To have a better understanding of GA in shading design, this study developed a systematic review of the literature examining shading design via GA in the Scopus index, based on the systematic review process, PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses). Once the selection criteria and the performance criteria were established, 23 publications of literature were included in the review. The performance criteria for shading design reviewed in the publications include functional aspects related to visual and thermal comfort, user interaction, aesthetics, energy efficiency and environmental performance. The gaps in research and emerging trends suggested that there was a growing interest in using algorithmic design methods, especially GAs, to meet the multifaceted challenges of shading design. This paper aims to contribute valuable insights into the development of innovative shading solutions that effectively balance user comfort and energy demands, ultimately advancing the field of sustainable architectural design. This study highlights the critical need for further exploration in the algorithmic design of shading systems and offers more effective solutions to contemporary challenges of sustainable space design.

Daylighting is essential to the well-being of occupants in educational spaces. It increases students’ performance and provides an opportunity for achieving energy efficiency, as well as indoor visual and thermal comfort. However, daylight performance is rarely accounted for when taking decisions attributed to building renovation. This results in increased or decreased daylighting lighting levels and glare which jeopardizes the functional requirements of the space. Hence, this study adopted a mixed qualitative/quantitative approach to compare two recently renovated educational spaces (architectural design studio drawing halls) in terms of the effect of renovation activities on daylighting and visual comfort, noting that both spaces were located in the same building and subject to similar prevailing climatic conditions. This included a sequence of site measurements, surveys and simulations. The results showed great variation between both studied spaces in terms of daylight efficiency and visual comfort. Some design proposals were tested in order to deduct learnt lessons for proper accounting of daylight during building renovation plans.

Recent studies on light shelves found that building energy efficiency could be maximized by applying photovoltaic (PV) modules to light shelf reflectors. Although PV modules generate a substantial amount of heat and change the consumption of indoor heating and cooling energy, performance evaluations carried out thus far have not considered these factors. This study validated the effectiveness of PV module light shelves and determined optimal specifications while considering heating and cooling energy savings. A full-scale testbed was built to evaluate performance according to light shelf variables. The uniformity ratio was found to improve according to the light shelf angle value and decreased as the PV module installation area increased. It was determined that PV modules should be considered in the design of light shelves as their daylighting and concentration efficiency change according to their angles. PV modules installed on light shelves were also found to change the indoor cooling and heating environment; the degree of such change increased as the area of the PV module increased. Lastly, light shelf specifications for reducing building energy, including heating and cooling energy, were not found to apply to PV modules since PV modules on light shelf reflectors increase building energy consumption.

Daylighting is an effective method in creating a comfortable visual environment and energy efficiency in university buildings. The potential for energy savings through daylighting studies is great was investigated using a case study approach on the three design studios in KAED Building, International Islamic University Malaysia (IIUM). The methodology simultaneously undertook field measurements and opinion surveys in the studios facing north, south, and northwest. Daylighting measurements using the Lux-Meter and calculations of the lighting energy consumption were conducted. The questionnaire survey was distributed to the users of the studios to assess their opinions on visual comfort. The results showed that the lighting levels were not up to the required standard. However, the lack of daylight did not hinder the users' visual comfort. The study proposed changing the existing less-efficient Fluorescent-T8 lamps to the more-efficient LED (light-emitting diode) lights for energy efficiency. Calculations on the annual energy consumption yielded a 40% reduction in the lighting bills and a payback period of around five years.

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Subdivided venetian blind control strategies considering visual satisfaction of occupants, daylight metrics, and energy analyses