Passive Daylighting Research Articles

Advanced passive technologies for double-glazed windows daylight and solar control and their performance investigation: A review

Window, as a part of building envelope, can always provide outside visual for indoor occupants and effectively impact the indoor daylight and thermal environment and occupants’ health. Over the past decades, the demand for optimal indoor environments has been steadily increasing. In response to this need, several technologies integrated within conventional double-glazed (DG) systems for solar energy and daylight regulation were developed and investigated. This paper aims to comprehensively review the daylight, solar control of existing advanced passive technologies of DG windows for further building energy consumption reduction, focussing on Transparent Insulation Materials (TIM) and adaptive passive thermotropic (TT) materials. From the review of current studies, it can be concluded that, the traditional smart thermotropic DG window can effectively control glazing spectral response to prevent indoor occupants from over-illuminated and daylight glare, however, occupants’ view communication with the external environment was totally blocked when the TT material was in its translucent state. Meanwhile, TIM window systems can improve the indoor daylight and thermal comfort, but they also have some limitations, for example, they have fixed visible light and solar optical properties. As a result, a DG window integrated with TIM may allow less solar heat and visible light to be transmitted into a building space, which may lead to a lower cooling energy demand in summer but a higher heating energy consumption in winter and also a higher electric lighting requirement. To effectively avoid the disadvantages brought by windows integrated with single TT or TIM system, TT-TIM-coupled window system is recommended to further improve the passive daylight and solar control technologies in the future.

COURTYARD VISUAL COMFORT ISSUES IN COMMERCIAL BUILDING IN TROPICAL CLIMATE MALAYSIA

Courtyards, while effective as multifunctional open spaces and passive daylight strategies in buildings, face challenges in tropical climates such as visual discomfort due to intense solar radiation. Visual discomfort impacts outdoor activities, affecting the efficiency of courtyards. To understand this issue, Setia Walk Puchong has been selected as a case study. Observation, fieldwork measurement, and simulation are methods used in investigating visual comfort performance. The main issues identified include uneven light distribution, glare, and insufficient shading, suggesting the need for effective design solutions. Given the context of tropical climates, the study aims to explore architectural strategies that can enhance visual comfort and ensure courtyards remain functional and usable spaces. This involves adapting designs to mitigate issues such as uneven lighting, glare, inadequate shading, and other factors that impact comfort in courtyards. Optimal configurations like small, deep, and decentralised courtyards are among the strategies to provide shade effectively. Choosing elements such as layered greenery and independent structures that can help mitigate glare and manage illuminance levels are other strategies for ensuring courtyards are functional and inviting spaces in tropical climates.

Efficiency Analysis of a Passive Daylighting System Based on Northern Malaysia’s Climate

Daylighting design strategy is important in order to have adequate lighting source in a room and necessary to decrease energy consumption for artificial lighting. Passive daylighting system utilizes daylight by collecting, reflecting and diffusing the natural light throughout a given area. The purpose for this study is to monitor, compare and analyse an optimum light pipe system design that can scatter daylight into a room based on three case studies. Lighting analysis was conducted using Autodesk 3ds Max Design software throughout the project based on the actual geographical parameters of Universiti Malaysia Perlis, Malaysia and also using the real sun azimuth on working hours. The results were compared according to the respective designs in order to observe the maximum internal illuminance and the average internal illuminance. The results show that the straight geometry with low aspect ratio produces the highest interior light intensity among other light pipe systems and the average internal illuminance values in the room was able to reach the minimum requirement of a small room which is 200 – 500 lux.

Thermal analysis of tubular daylight guidance system on an insulated flat roof with overlying soil

As an emerging passive daylighting technology, tubular daylight guidance systems (TDGSs) are increasingly used in low-energy buildings. However, TDGS may become a thermal bridge to increase indoor air conditioning load. To avoid an increase in total energy consumption, the thermal analysis of a flat roof section with a TDGS is simulated using CFD in this work. Additionally, the simulation compares the heat transfer performance of a conventional TDGS with eight different designs TDGS that contain additional glass unit. The findings show that TDGS has a thermal bridging effect on an insulated flat roof with overlying soil. The additional glass unit in the middle of the conventional TDGS with diameter 500 mm decreases its overall heat transfer coefficient by 53 %. Further, the same thickness of glass is divided into 4 layers and evenly distributed inside the TDGS with diameter 500 mm, which can reduce the total heat transfer coefficient of the conventional TDGS by 67 %.

Optical modeling and computational analysis of improved daylight collector geometry for a tubular skylight.

A carefully designed daylight collector for a tubular skylight is necessary to serve the occupants' illumination needs under the dynamic trajectory of the sun. This work simulated an improved configuration of a passive daylight collector comprising parabolic and conical reflectors in a modeled room using the lighting software tool TracePro. Results indicated that the lighting performance of the proposed design configuration was significantly enhanced under low altitude sun in comparison with conventional tubular skylights (with revolved parabolic and cylindrical reflectors) [Light. Res. Technol.52, 495 (2020)10.1177/1477153519872794] and hemispherical transparent dome as daylight collectors by more than ∼30%-40% and ∼110%-130%, respectively.

Comprehensive investigation of a building integrated crossed compound parabolic concentrator photovoltaic window system: Thermal, optical and electrical performance

Integrating PV solar cells with concentrators into window systems can not only generate electricity for a building, but also has the potential to enhance the thermal resistance of the building's windows without a significant sacrifice of light transmittance for passive daylight. A novel system, known as the crossed compound parabolic concentrator photovoltaic window, has been recently studied for its electrical properties. However, its thermal and optical performance, particularly in terms of the overall heat transfer coefficient (U-value) and total optical transmittance when integrated into a building, remains unexamined. These factors are crucial for predicting the system's impact on a building's energy efficiency and indoor comfort. Therefore, this paper aims to investigate the U-value of this window system under various temperature scenarios and the optical transmittance of the window at different incident angles. The thermal conductance was assessed through numerical simulations using a computational fluid dynamics model, which was validated by experimental measurements conducted in a large climate chamber. The optical transmittance was investigated using a validated 3D ray-tracing model. The total optical transmittance and electricity generation were calculated for typical sunny days in winter and summer under London's climate conditions. Additionally, alternative designs were developed to explore the impact of pitch between adjacent optics on the thermal conductance and optical transmittance of the window. The results showed that the window with a configuration of Dx = Dy = 5 mm (where Dx and Dy represent the horizontal and vertical pitches, respectively, between two adjacent solar optics) achieved the lowest U-value (2.566 W/m2·K). This U-value is slightly lower than that of the original window design, which has a U-value of 2.575 W/m2·K. The original window configuration with Dx = Dy = 1.77 mm produces the highest power output. Specifically, it generates 499.25 Wh/m2 on a typical sunny day in winter and 162.73 Wh/m2 on a typical sunny day in summer. However, it exhibits the lowest transmittance (14.6 % on a typical sunny day in winter and 25.2 % on a typical sunny day in summer, respectively), indicating that it is more suitable for buildings with a higher window-to-wall ratio to ensure an adequate amount of natural light. For buildings with a lower window-to-wall ratio, the CCPC-PV window should be designed with a larger horizontal pitch, such as 15 mm and 30 mm, to meet indoor illuminance requirements while also providing enhanced thermal performance and additional power output.

Students’ Perception of the Natural Daylighting in Higher Education Design Studios

An energy-efficient and environmentally friendly building are key to establishing green buildings. Both key concepts are predominantly significant in today's sustainable development concept. Higher education institutions have started their green and sustainable campaign to meet the government's initiative to reduce energy consumption. Energy consumption is increasing annually, whereby for the past 10 years, energy usage in government buildings has increased from 50,000 GW to 109,000 GW per year. The electricity bills increased due to the extensive use of artificial light. Artificial lighting is used extensively during the daytime in higher education buildings due to poor passive daylighting strategies in many buildings. Therefore, this paper intends to present the findings of a comprehensive and systematic analysis of students’ perceptions of natural daylight in design studios in higher education buildings. Survey-based investigations were conducted to analyse the student's perception of natural daylight. 149 questionnaires were distributed to Interior Design students from higher educational institutions. The data is being analysed using statistical analysis with the use of SPSS as the tool for analysis. The research found that the respondents prefer brighter natural daylight to artificial lighting in the studio. However, their design studio receives a high glare and thermal heat. The high glare and thermal heat subsequently made the respondents feel inconvenienced and uncomfortable due to glare and heat gain. As this paper only provides students' perceptions about natural daylight in the design studio, further study is needed to identify types of daylight strategies used in the design studio.

A simulation-aided approach in examining the viability of passive daylighting techniques on inclined windows

As the construction industry moves towards sustainability, buildings are frequently constructed using eco-friendly building materials and techniques. It is important to evaluate various passive daylighting techniques in order to obtain natural light into the building in the most eco-friendly manner feasible. As part of our investigation, the office in study has inclined windows, limiting the amount of solar radiation entering and shielding the building occupants from direct sunlight. Thus, it is critical to identify an appropriate passive daylight design that reduces renovation work without disrupting mechanical, electrical, and plumbing (MEP) services. By using photorealistic simulation and Radiance daylight simulation to compare various types of light shelves across different levels, it offers a practical solution with low installation costs to address inadequate daylighting with inclined windows. This will assess the effectiveness of daylight penetrations and enhance visual comfort in a high-rise structure with inclined windows. Our research findings demonstrate that, even when installed on inclined windows with daylight infiltrations, the combination of tilted light shelves performs better in reflecting daylight into the internal space, with an estimated 34% better performance and a more than 25% reduction in energy usage. Aside from daylight simulation, the chiller load simulation results show that the combination of tilted light shelves has no effect on the chiller loads, indicating that no heating is involved. Our work here has the potential to enhance sustainability without requiring extensive retrofitting or changes to the original interior design, resulting in lower installation and renovation costs while improving occupant health and welfare at the same time.

STRATEGIES IN IMPROVING THE BUILDING EFFICIENCY AND DAYLIGHTING: A CASE STUDY OF GREEN BUILDING

Malaysia is one of the rising countries with the highest energy consumption rate, which is attributable to strong economic development in the residential and commercial sectors that consume approximately half of the total electricity generated. Several criteria have been implemented in Malaysia to develop efficient building design, such as the Green Building Index (GBI) and Passive Daylighting Strategies. The study aims to investigate passive daylighting solutions for different building orientations and facade materials to measure energy efficiency through building designs. Buildings are a variable that contributes to growing energy consumption resulting from population increase and climate change. The building facade is a factor that could control the indoor environment, which affects the energy consumption in buildings. A case study determined the elements that maintain building efficiency and electric savings by examining two buildings certified by the Green Building Platinum and the Ministry of Finance (MoF). Low consideration of Passive Daylighting Strategies in building designs allows direct sunshine and increases the use of air conditioning to maintain the room at a comfortable temperature.

A Study of Daylighting Impact at Inpatient Ward, Seri Manjung Hospital

Over the past few decades, there has been a growing interest in passive design strategies in the built environment, such as daylight. Using sunlight as the source, passive daylighting aims to provide effective natural lighting into the building while retaining maximum visual comfort without using mechanical equipment. Various research has shown the benefits of the natural environment to aid in human recovery, including daylighting. The majority of the biophilic design studies focused on workplace and healthcare environments such as hospital design. While biophilic architecture brings the meaning of nature to the internal environment, the positive effects of this biophilia are particularly concerned on healthcare facilities as it puts an element of extreme pressure on the space. This paper aims to understand the relationship between the patients and staffs’ experiences of their physical environment, specifically addressing the use of daylighting as aiding the recovery of patients and restorative impact for the users. This paper investigates the effects of daylighting in the inpatient ward at Seri Manjung Hospital through a set of questionnaires distributed to the 50 respondents of male and female users aged18 and above. This inpatient ward space is built with windows and utilising natural lighting during the day.The participants were asked to share their experience on the lighting conditions in the ward space and the impact on their health and recovery. The outcome of this study has shown that passive daylighting technique and biophilic design in inpatient wards help to increase users' connectivity with nature, improve physical and psychological well-being and accelerate the recovery process. Consequently, incorporating passive daylighting and biophilic design in a healthcare setting will shift the hospital's design to be more sustainable and responsive to the environment

Energy Savings of an Optimized Daylight-Pipe System With Single and Dual Reflectors in Tropical Climates of India

Abstract Buildings in India consume over one-third of the country’s total electricity consumption and out of which about 28% and 25% are accounted for lighting energy in the residential and commercial buildings, respectively. Passive daylighting system using tubular daylight-pipe is a promising technique to save lighting energy by illuminating deep building interiors that have no daylight access through exterior windows. In this study, an innovative daylight-pipe has been designed and developed for enhanced daylighting performance by optimizing configurations of single and dual reflectors at its receiver. A detailed daylight assessment has been carried out using controlled experimentation while varying the reflectors position and orientation inside the hemispherical receiver of the daylight-pipe. It has been found that the single reflector oriented toward south has the best performance with a light transmission efficiency of 35.6%. Furthermore, monthly electrical energy savings due to the advanced daylight-pipe along with various supplementary electrical lighting options such as incandescent bulb, compact fluorescent lamp (CFL), and light emitting diode (LED) were estimated and compared for various climatic locations of India. From these evaluations, a lighting energy saving up to 23% has been observed in the summer month of May for temperate climate of Pune and hot-dry climate of Jodhpur.

Numerical evaluation of an optically switchable photovoltaic glazing system for passive daylighting control and energy-efficient building design

Adaptive control of solar heat gain and visible light transmission through windows is perceived to be a potential measure for enhancing energy conservation and visual comfort in buildings. In this study, a novel versatile window, named Building Integrated Photovoltaic (BIPV) smart window, was proposed to offer simultaneous improvement of daylighting control, on-site electricity generation and building energy efficiency, compared to traditional BIPV windows with static optical properties. The key components of the proposed system include an optically switchable thermotropic layer made of Hydroxypropyl Cellulose (HPC) hydrogel, crystalline-silicon photovoltaic cells, clear glass and low-emissivity (low-e) glass covers. The thermotropic layer can respond to heat by autonomously changing its visible and near-infrared optical properties, with which the amount of solar radiation into building spaces can be manipulated and thus the risks of excessive solar heating and illumination can be prevented. Apart from excellent solar modulation, the BIPV smart window can collect a proportion of the light scattered from the thermotropic layer and concentrate it onto the integrated PV cells for extra electricity generation. An innovative methodology has been proposed to predict the optical, thermal and electrical properties of the BIPV smart window under varying ambient conditions. Numerical simulations have been carried out in EnergyPlus to predict the window's performance when it is applied to an office-type environment in the climate of Nottingham, the UK. The influence of different window design scenarios, in terms of Window-to-Wall Ratio (WWR), orientation and transition temperature, has been investigated. It was found that using the BIPV smart window can achieve an annual energy saving of 36.6% but also a more comfortable indoor luminous environment, compared to the counterpart BIPV window (with no thermotropic layer integrated), when installed in the south-oriented office with a WWR of 25%.

Review of Active and Passive Daylighting Technologies for Sustainable Building

According to the International Energy Agency, nearly 20% of worldwide electricity is used up by lighting. This is equal to the total electricity nuclear power generates. Thus, it is needy to explore new technologies for direct use of sunlight via integrating daylight system to the building, which is cost-saving, environment-friendly, and a green solution rather than indirect conversion of electricity to lighting even from renewable sources. In this paper, we present a review on the existing technologies of daylighting systems up to date and how they can provide lighting in a building interior via collection and distribution of sunlight. Our review is a comprehensive study to embrace both passive daylighting system with stationary design and active daylighting system equipped with sun tracking. The economic feasibility, general challenges, and prospects of daylighting systems are also discussed to understand the existing problems that hinder the extensive deployment of daylighting systems. In conclusion, more research works are needed in improving the technological development of a daylighting system so that it is more affordable, environment-friendly, less energy-intensive, and easy to install and gives uniform illumination for the effective application in both commercial building and residential houses.

Passive Daylighting Systems

Passive daylighting approaches stimulate the quantity and even distribution of daylight throughout a building by collecting natural light and reflecting it into darker areas of the building. What makes this a “passive” approach is that the design elements do not require any special mechanical equipment.

Passive Daylighting Design Strategies of Colonial Mosques in Malaysia

This study aims to investigate the daylight performance of Colonial Mosques in Malaysia. The first objective of this study is to identify passive daylighting strategies from the colonial mosques. The second objective of this study is to evaluate the daylight performance of the colonial mosques. The research methodology consisted of table research, field observation, and daylight analysis simulation of the prayer hall in the Colonial Mosques, using Sefaira daylighting simulation software. The results have shown that the daylight in Colonial Mosques was affected by the building orientation, shading elements, window to wall ratio, and window type. It was also found that the clerestory window type enhances indoor daylight performance. Keywords: Passive Daylighting, Colonial Mosques. eISSN: 2398-4287© 2021. The Authors. Published for AMER ABRA cE-Bs by e-International Publishing House, Ltd., UK. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer–review under responsibility of AMER (Association of Malaysian Environment-Behaviour Researchers), ABRA (Association of Behavioural Researchers on Asians/Africans/Arabians) and cE-Bs (Centre for Environment-Behaviour Studies), Faculty of Architecture, Planning & Surveying, Universiti Teknologi MARA, Malaysia.

Potential of Solatube technology as passive daylight systems for sustainable buildings in Saudi Arabia

Saudi Arabia is one of the most important countries that have an abundant potential of renewable energy resources in form of solar and wind energy. In light of Saudi Arabia's vision 2030, renewable energy should fractionally replace fossil fuel in energy production during the different aspects of life in the next few years. As a result of the distinguished geographical location of Saudi Arabia, in the sun-belt zone, solar energy projects have contributed to a wide field during the past few years in smart city projects as well as sustainable building initiatives. Most of the solar energy applications in Saudi Arabia's sustainable buildings have been directed to solar thermal and photovoltaic technologies. However, the utilization of passive solar daylighting systems in Saudi Arabia's sustainable buildings has received little attention, although it can save about 20–30% of the total electrical energy consumed. Recently, Solatube technology has received great attention globally due to the positive environmental impact and the resulting internal health conditions. Solatube system can transport efficiently the daylight into the interior spaces and achieve visual comfort without excessive heat. In the present paper, the potential of Solatube technology in Saudi Arabia's sustainable building sectors is evaluated and the required climate conditions are discussed. Different other aspects will be also discussed related to the Solatube daylight systems such as the different types of Solatube systems, the different applications of Solatube daylight systems, and the illustration of the previous case studies of Solatube daylight systems in different countries. In general, it is concluded that Saudi Arabia as one of the largest solar energy producers and has widespread desert land and year-round clear sky is very suitable for adopting Solatube technology in different sustainable building sectors.

Comparative study of acrylic flat plate and dome shaped collector for summer and winter solstice conditions

In the presented study, an acrylic flat plate passive daylight collector is compared with the acrylic dome shaped daylight collector for 21st June (summer solstice) and 21st December (winter solstice) day. Daylighting system with both acrylic dome shaped and flat plate collector was designed and simulated using TracePro, an optical designing and simulation tool. A highly reflective light pipe with reflectivity of 95% was utilized as a light transportation device. Collectors are made up of Polymethyl methacrylate (PMMA), boasting higher transmission efficiency, weather resistant and shock resistant properties than glass, easy to manufacture, light weight and cost-effective alternative to glass. Simulations performed for the Chandigarh location showed that the dome shaped collector delivered better results than the flat plate collector.

A simulation-aided approach in improving thermal-visual comfort and power efficiency in buildings

Thermal and visual comfort are important for the health and productivity of occupants in office buildings. In this paper, we present a simulation-aided approach in analyzing and optimizing lighting and thermal conditions in building interiors, encompassing the modelling of the interior space in virtual facilities, ray-tracing simulations for illumination prediction, and computational fluid dynamics/heat transport simulations for airflow and ambient temperature predictions. This is carried out with the aim of optimizing visual-thermal comfort in an indoor environment while adhering to comfort and safety guidelines. We demonstrate the methodology on a real-world case study on an office building in Singapore, improving lighting and thermal conditions greatly through passive daylight fixtures and the reconfiguration of climate-control air supply vents within the office space. A significant reduction of energy consumption was simultaneously achieved, amounting to >7% in lighting and cooling expenditure. The presented methodology allows rapid iteration and evaluation over plausible designs in enhancing indoor environmental quality and building energy performance, especially relevant when performance and sustainability goals have to be balanced.

Daylighting Retrofit Methods as a Tool for Enhancing Daylight Provision in Existing Educational Spaces—A Case Study

Adequate illuminance has a great effect on the health, comfort, and performance of pupils. It can be achieved by either artificial lighting or daylighting. Daylighting is usually preferred due to psychological, physiological, and economic purposes. This study aims to improve the daylight provision in existing classrooms, by investigating various retrofit methods for passive daylighting techniques in northerly oriented classrooms at Jordan University of Science and Technology (JUST). Data for this research are obtained using computer simulation. The retrofit methods are evaluated in terms of illuminance levels on the desks plane and the chalkboard. The retrofit methods investigated in this study included improving the material reflectance, adding clerestory to the classroom, lightshelves, anidolic ducts, as well as various combinations between these cases. By comparing the results, and in light of the recommended lighting level by The Lighting Guide 5: Lighting for Education released by Chartered Institution of Building Services Engineers (CIBSE) in 2011, the combination of the clerestory window and the anidolic ducts result in the best results. While CIBSE recommended a target illuminance of 300 lx on desks plane and 500 lx on the board, the combination registers an average of 249 lx–300 lx on the desks plane in all sensors compared to 42 lx–105 lx in the base case, and an average of 275 lx–345 lx on the board for the tested dates compared to an average of 45 lx–115 lx in the base case.

Optical fiber light scattering outdoor tests for interior daylighting

In building construction, most traditional building materials block the passage of natural light through the building envelope into its interior space. Therefore, there is an energy demand for artificial lighting of interior spaces during daytime hours in almost all building types. Currently, some interior spaces in a building may have excessive sunlight exposure and as a result, external shading elements for daylight control are required. Optical fibers (OFs) are mainly used for data transmission, but previous studies have demonstrated their capability for capturing and channeling sunlight into interior spaces in an anidolic manner. The present research introduces different OF tip shapes aligned together with solar concentrators of different geometries. The objective of the study is to assess and improve the basic properties of sunlight capturing, channeling and scattering using OFs. The results demonstrate the viability of using OFs as a passive daylight system and as an advancement in the energy efficient building envelopes design.