Daylight Integration Research Articles

Replacement of tubular fluorescent lamps with tubular LEDs lamps and daylight integration in classrooms and laboratories

The quality of lighting significantly influences our ability to perform tasks in enclosed spaces, and certain characteristics of lighting sources play a crucial role. Light-emitting diode (tubular LED) lamps offer advantages for both home and office use. Choosing tubular LED lamps over fluorescent ones is beneficial for several reasons. Tubular LEDs are mercury-free, ensuring environmental safety compared to the small amount of mercury present in fluorescent tubes. Furthermore, tubular LEDs provide directional lighting, minimizing light loss in fixtures and unnecessary areas, and offering better efficiency (around 40% more than tubular fluorescent lamps). Also, they produce high-quality light with various color temperatures, eliminating flickering issues that can cause discomfort such as eye strain, headaches, and migraines. Additionally, tubular LEDs have a longer lifespan making them a preferable lighting option. The superior quality of natural light makes it the optimal source of illumination, which matching well with the visual response of the human eyes. Daylight has a positive influence on people, instilling a feeling of vibrancy and brightness within their living environment. The acknowledged benefits of daylight extend to enhancing visual comfort, promoting health, and improving overall performance among building occupants. This paper focuses on the integration of natural daylight with artificial light, particularly through tubular LED lamps, and investigates the daylight factor. Two groups of six tubular LED lamps (60cm with 9 Watt and 120cm with 18 Watt) and another group of six tubular fluorescent lamps (60cm with 18 Watt and 120cm with 36 Watt) were studied. The study involved two sets of six tubular LED lamps (60cm with 9W and 120cm with 18W) and another set with six tubular fluorescent lamps (60cm with 18W and 120cm with 36W). Measurements were conducted using Spectroradiometer Ocean Optics HR 2000 with 4.7% uncertainty and a photometric bench to assess the spectral output. Additionally, UVA/B silicon detector and Luxmeter detector setups with uncertainties of 5.2% and 6%, respectively, were employed for irradiance and illuminance measurements of tubular LEDs and fluorescent lamps. Various parameters, including daylight factor ratio, UVA power to luminous flux (K) for tubular fluorescent lamps, spectral power distribution, and illumination levels were obtained. Integration between daylight and tubular LED lamps was also determined. The maximum detected value lmW /013.0  is less than the safe limit for human health but still there are effects on human health if they use these types of lamps. Therefore, it is advisable to switch from tubular fluorescent lamps to tubular LEDs to mitigate the impact of UVA on human health and the environment.

Integrating Digital Twins with BIM for Enhanced Building Control Strategies: A Systematic Literature Review Focusing on Daylight and Artificial Lighting Systems

In the architecture, engineering, and construction industries, the integration of Building Information Modeling (BIM) has become instrumental in shaping the design and commissioning of smart buildings. At the center of this development is the pursuit of more intelligent, efficient, and sustainable built environments. The emergence of smart buildings equipped with advanced sensor networks and automation systems increasingly requires the implementation of Digital Twins (DT) for the direct coupling of BIM methods for integral building planning, commissioning, and operational monitoring. While simulation tools and methods exist in the design phase of developing advanced controls, their mapping to construction or post-construction models is less well developed. Through systematic, keyword-based literature research on publisher-independent databases, this review paper gives a comprehensive overview of the state of the research on BIM integration of building control systems with a primary focus on combined controls for daylight and artificial lighting systems. The review, supported by a bibliometric literature analysis, highlights major development fields in HVAC controls, failure detection, and fire-detection systems, while the integration of daylight and artificial lighting controls in Digital Twins is still at an early stage of development. In addition to already existing reviews in the context of BIM and Digital planning methods, this review particularly intends to build the necessary knowledge base to further motivate research activities to integrate simulation-based control methods in the BIM planning process and to further close the gap between planning, implementation, and commissioning.

Representing the photobiological dimension of light in northern architecture

Daylight can enhance the quality and inhabitability of architecture through a better relationship with the exterior environment, especially by its intensity, chromaticity and ability to synchronize the human circadian clock. Daylight integration in architecture remains a challenge in Nunavik (Quebec, Canada) due to its subarctic climate, photoperiod and solar geometry. The objective of this research is to implement photobiological metrics of light in architectural representations by isolating the photopic (daytime vision) and melanopic (circadian clock) portions of the electromagnetic spectrum, and to spatialize daylight and artificial light in relation to landscapes and indoor architectural spaces. An automated and low-cost capture tool based on Raspberry Pi microcomputers and Camera Modules (RPiCM) captures high dynamic range images, which accurately measure luminance to render human perception. Absolute photopic luminance maps (cd/m2) are supplemented with false colour displays of photopic/melanopic contents of light regarding building surface materials. The research develops photometric captures of absolute photopic and melanopic illuminance (lux, EML). Photobiological metrics of light are integrated into a set of physical properties of lighting patterns to perform light assessments and are ultimately represented as a graphical display to help designers and researchers to evaluate architectural interior–exterior relationships through daylight qualities.

Real-Time Investigations and Simulation on the Impact of Lighting Ambience on Circadian Stimulus

Indoor lighting, incorporated with visual and circadian needs, is the upcoming goal of lighting designers. In tropical and subtropical regions, where more daylight is available, daylight harvesting is a prime source of ambient lighting indoors. This paper aims to study various cases of lighting ambience to investigate the circadian lighting capability in terms of the circadian stimulus (CS) of the system under consideration. The instances considered are simulation studies in an open office plan and real-time experimentations in a test workbench and a faculty cabin. Daylight integration was undertaken through controlled venetian blinds, tunable sources and a commercially available human-centric lighting system. The result and analysis show the influence of spectrally tunable light sources on CS rather than fixed light sources. Due to the varying CCT of tunable LED luminaire, circadian stimulation for an occupant can be easily incorporated without crossing the limits of vertical and horizontal illuminance, which may lead to visual discomfort. The findings from this study reveal that daylight–artificial light integration scheme with controlled shading and spectrally tunable source provides the optimal solution for glare-free, energy-effective and circadian entrainment, i.e. human-centric lighting (HCL). With the help of simulations, pre-evaluation will aid the lighting engineers in making a better choice among the various lighting-controlled schemes to implement HCL in indoor office spaces.

Design and Development of task light simulator for Quality Lighting Factor and Simulation of LED tubebased Illumination system for Laboratory

Daylight is only the natural light available surrounding us which is mostly useful in outdoor use. Artificial lighting is used to a greater extent in the world for a variety of indoor as well as outdoor applications. The fundamental requirement of light is to see the objects in a dark time. Nowadays powerful light sources are developed to fulfill the fundamental requirement and the quality illumination. Quality lighting provides uniform distribution in space, good color rendering, and adequate light. The requirement of every task is different and the quality of lighting depends on a number of factors, so there must be a database available that will provide recommended values for a given task. Though there are several simulation software available for analysis of illumination, they are able to provide only information of illumination pattern based on user inputs. There is a need fora user-friendly GUI (Graphical User Interface) which provides necessary parameter values for good lighting design and spectral power distribution of different LED (Light Emitting Diode) sources. The main aim of this work is to model and simulation of spectral characteristics of monochromatic and white LED. Develop a MATLAB-based GUI to select recommended values for different tasks according to Illuminating Engineering Society (IES) standards which helps lighting designers for selection of proper light sources. Uniform illumination is obtained and energy is saved by the integration of daylight with artificial light. A case study of LED tube-based glare-free illumination for the laboratory is also reported

Low-cost smart solutions for daylight and electric lighting integration in historical buildings

Research have shown that the correct integration of daylight and electric lighting reduces the energy use in buildings, while improving visual comfort. Smart shading systems, especially those electrically controlled, play an important role to control solar radiation. Similarly, smart and dimmable/tunable lighting can help to adjust the artificial light to the real users’ needs. This paper presents preliminary results of an ongoing living lab study investigating how artificial lighting systems can be integrated with shading systems, placing human comfort at the heart of the study and yet saving energy. A manually controlled, commercial and low-cost smart system integrating two motorized shading devices and six dimmable LED luminaires with a different selection of CCT were installed in a private office in a historical building. Indoor and outdoor lighting conditions and energy consumption associated to the lighting system are constantly monitored to assess how the people use shading and lighting upon varying the boundary conditions.. Preliminary results highlight that users prefer to maximise daylight on the work plane as well as they generally use both shading and electric lighting systems in response to boundary conditions that cause serious discomfort.

Examining the Impact of Daylighting and the Corresponding Lighting Controls to the Users of Office Buildings

Daylight utilization significantly contributes to energy savings in office buildings. However, daylight integration requires careful design so as to include variations in daylight availability and maintain a balance between factors such as lighting quality and heat gain or loss. Designers with proper planning can not only improve the visual environment and create higher-quality spaces, but simultaneously minimize energy costs for buildings. The utilization of photosensors can exploit the benefits of daylighting by dimming the lighting system, so that no excessive luminous flux is produced, thus leading to energy savings as well as visual contentment. However, the human factor is crucial for the proper function of a lighting control system. Without its acceptance from the users, energy savings can be minimized or even negligible. The objective of this paper is to present a post-occupancy evaluation regarding occupant satisfaction and acceptance in relation to daylighting in offices equipped with automated daylight controls. In addition, the response of the users was compared with lighting measurements that were performed during the post-occupancy evaluation. Three case studies of office buildings with installed daylight-harvesting systems were examined. The age of the occupants was a crucial factor concerning their satisfaction in relation to the lighting levels. Aged users were more comfortable with lighting levels over 500lx, while young users were satisfied with 300lx. The impact of different control algorithms was outlined, with the integral reset algorithm performing poorly. The acceptance of the users for the closed loop systems maintained the expected energy savings of the daylight harvesting technique. Most of the occupants preferred to use daylight as a light source combined with artificial light but having the control to either override or switch it on and off at will. The results shown that a post-occupancy survey along with lighting measurements are significant for making an office environment a humancentric one.

Daylight integrated indoor VLC architecture: An energy‐efficient solution

AbstractIn an indoor space, visible light communication (VLC) can form a promising enhancement of future illumination infrastructures with communication functionalities. This illumination infrastructure consumes 20% of the total energy consumption in the world. In this perspective, daylight integration with indoor VLC system is a promising area of research to conserve a considerable amount of energy. This paper deals with the design and practical realization of an energy‐efficient indoor VLC system through daylight integration. Dimming control mechanism using continuous current reduction topology is adopted to design the transmitter section of the VLC system. Thrust has been given to accomplish the required communication performance in terms of the bit error rate and illumination performance in terms of average horizontal illuminance and short‐term flicker severity. Both the communication and illumination performances have been evaluated under five different daylight conditions. At maximum ambient daylight condition, 37.29% of total energy has been saved, while the bit error rate lies in the order of 10−10. Simultaneously, satisfactory illumination performance in accordance with international guidelines has been achieved.

Evaluating performance of daylight-linked building controls during preliminary design

Abstract Thanks to the spread of new light sources and of smart dynamic control systems, automation sector has begun to play a fundamental role in lighting design. In this regard, daylight-linked control systems (DLCSs) represent a particularly interesting research field, since they offer great opportunities both in obtaining energy savings and in improving visual comfort conditions. However, their use is not so spread, because of the difficulties in predicting their functioning during the design process and in evaluating their effective energetic and economic advantages: available technical solutions are so many that design choices can be very hard for specialists. To overcome these obstacles, a precise assessment methodology is needed. Given these premises, the goal of the paper is to show the effectiveness of new performance parameters (Daylight Integration Adequacy, Percentage Intrinsic Light Excess, Percentage Light Waste and Percentage Light Deficit) in order to evaluate DLCs performance and to underline which factors mostly affect their functioning.

Performance Analysis of Windows with Integration of Daylight and Artificial Light: A Case Study

Rapid pace of urbanization has made city as a black hole for energy demand. Building sector alone consumes nearly 48 per cent of energy than other energy consuming sectors. There is great potential in buildings for reducing cooling load by carefully designing number of windows and indoor lighting with added benefits of increased occupant satisfaction. However, redesigning of the windows must be integrated with the visual comfort of the occupants. A case study is carried out in a conference hall of a University on integration of solar cooling load and visual comfort by redesigning the windows using IES-VE building energy software.

New parameters to evaluate the capability of a daylight-linked control system in complementing daylight

The use of daylight-linked controls (DLCs) can be a valuable design strategy to improve lighting conditions of indoor environment and to obtain considerable energy savings. These systems continuously adjust luminaires flux emission to maintain a constant illuminance level at the workplane, accounting for daylight availability. However, depending on their setting and operating conditions, they can provide more or less light than necessary, determining light excess or deficit at the workplane. Generally, the quality of control strategies is measured through achievable energy savings, but this approach is too inaccurate, since it does not inform about the ability of the system to provide adequate lighting conditions. Given that, the paper proposes new indices to describe DLCs performances: Daylight Integration Adequacy (DIA), Percentage Light Deficit (LD%), Percentage Intrinsic Light Excess (ILE%) and Percentage Light Waste (LW%). DIA (and complementary parameters DIA− and DIA+) describes the occurrence of different control operating conditions (ideal functioning, intrinsic light excess, light deficit and light waste) during a specific period. LD%, ILE% and LW% define the quantity of wasted or lacking light. Moreover, a simple case study is presented, in order to demonstrate the simplicity in calculating these parameters and their usefulness.

Estimation of Energy Savings Due to the Integration of Daylight with Artificial Lighting in Classrooms

Estimation of Energy Savings Due to the Integration of Daylight with Artificial Lighting in Classrooms

Assessing window area and potential for electricity savings by using daylighting and hybrid ventilation in office buildings in southern Brazil

The aim of this study is to develop a method to assess window area based on electricity consumption in office buildings in southern Brazil. The method may be used in the preliminary building design process in order to help choose an adequate window area to minimize its impact on energy consumption, depending on climate, building size, solar orientation, and mode of operation. The method also considered thermal comfort and daylighting performance. Four cases were investigated: Case 1, building operating with artificial lighting and air-conditioning; Case 2, considering integration of daylight and artificial light with air-conditioning; Case 3, building operating with hybrid ventilation and artificial lighting; and Case 4, considering integration of daylight and artificial light with hybrid ventilation. EnergyPlus and Daysim simulation programs were used to estimate the electricity consumption for each model. The integration of daylighting with artificial light (Case 2) generates more potential for energy savings (PES) than hybrid ventilation (Case 3). Case 4 showed PES ranging from 4.2% to 64.9%, allowing larger window areas with lower consumption, resulting in the highest PES.

The Integration of Day Light with Advance Fuzzy Based Controllers for Institutional Buildings in the Region of Central Queensland, Australia

Smart buildings lately have gained momentum due to its ability to drive, manage and control energy conservation measures. Fuzzy based controllers in Building Management Systems (BEMS) can use the latest and the most innovative control strategies in order to achieve a comfortable life style while savings energy and reducing greenhouse gas emissions. This system uses real life events as a point of control. Those real life events may include day-light usage (natural light), occupancy profile, passive cooling techniques and the usage of ambient atmosphere based on its ambient temperature and humidity. This paper develops a BMS using advanced fuzzy based controllers with integration of day light. This control strategy is based on quantifying the outside and the inside illuminance and allowing an add-on controller to perform a photometric calculation and comparison to decide rooms openings (windows). The paper also analyses energy savings and recommend suitable markets for this control strategy either during the design stage of a building, or after the building construction or retrofitting.

Assessing Lighting Energy Saving Potential from Daylight Harvesting in Office Buildings Based on Code Compliance & Simulation Techniques: A Comparison

Daylighting is a cornerstone strategy aiming at reducing a building's energy consumption. Daylight responsive dimming is a proven, mature technology, that significantly reduces lighting energy use, which in turn, affects both energy consumption and peak loads as well. Although in Energy Performance Building Directive (EPBD), the use of a daylighting harvesting system is encouraged, the specifications are rather limited based on EN 15193:2007. According to literature, the potential for lighting energy savings from daylight integration, can approach 60.0%. Consequently, a more accurate and detailed calculation method could possible result in downgrading a building's energy performance rating, when compared with simplified procedures that may underestimate these savings.The paper builds on the authors’ previous work, providing an overview of the methods and techniques used to estimate lighting energy savings due to daylight harvesting. An extensive comparison is carried out between the resulting energy savings as estimated by the method adopted in EN 15193:2007 and its variation by the Greek Regulation for the Energy Efficiency of Buildings (KENAK), with savings calculated by more complex calculation methods that require the use of simulation tools.According to the results, great differences are observed in the estimated lighting energy savings between simulation and EN15193:2007. These differences still exist even when the parameters used in EN15193 are calculated by an external software affecting energy performance certificate rating.

Energy performance of windows in office buildings considering daylight integration and visual comfort in hot climates

In hot climates, the exterior envelope of office buildings can significantly contribute to the building's energy consumption. Windows are considered as a major source of heat gain and can contribute to the reduction of energy when daylighting is integrated with artificial lighting. However, with daylighting, the possibility of visual discomfort is likely to arise due to the uncontrolled light. The present study focuses on investigating the energy savings when daylight and artificial light are integrated while maintaining visual comfort. In order to assess visual comfort, both glare index and DaylightFactor are studied. A typical office in a hot climate is modeled using the simulation program, DesignBuilder. We predict the energy and visual performance for three different types of glazed windows. For all types of modeled windows a significant reduction in the annual cooling and building energy consumption was observed. For example, a 14% reduction in total building energy consumption was obtained with daylight integration for the double-glazed clear glass windows and a 16% reduction was obtained for double-glazed low-E windows. It has been observed that in all cases visual comfort was not achieved. By employing automatic interior shading control, visual comfort was achieved with no significant reduction in energy savings.

Potencial de economia de energia elétrica através do uso da luz natural e da ventilação híbrida em edifícios comerciais em Florianópolis

O objetivo deste estudo é estimar o potencial de economia de energia elétrica com o uso da luz natural integrada ao sistema de iluminação artificial e a utilização da ventilação híbrida em edifícios comerciais localizados em Florianópolis, SC. O trabalho foi baseado em simulações computacionais nos programas EnergyPlus e Daysim. Foram simulados modelos de ambientes de edificações comerciais, com três geometrias, três dimensões de sala por geometria, dez áreas de janela por modelo e quatro orientações. Os modelos foram examinados por meio de quatro estudos de caso. No Caso 1 (referência), a edificação opera com sistemas de iluminação e de condicionamento artificiais; no Caso 2, ocorre a integração da iluminação natural com a artificial, com condicionamento artificial; já no Caso 3, utilizam-se a ventilação híbrida e a iluminação artificial; no Caso 4, adotam-se a iluminação natural integrada com a artificial e a ventilação híbrida. Os consumos de eletricidade do Caso 1 foram comparados com os demais casos. Assim, foi estimado o potencial de economia de energia elétrica gerado pelo uso da luz natural e ventilação híbrida. Conclui-se que a utilização da iluminação natural e da ventilação híbrida em edificações comerciais localizadas em Florianópolis apresenta potencial de economia de energia elétrica de até 64,9% e que essas estratégias podem ser utilizadas para aumentar a eficiência energética desse tipo de edificação.

A Study on Daylight Integration with Thermal Comfort for Energy Conservation in a General Office

Lighting control systems deliver the correct amount of light at the right time and right place. Lights can automatically turn on, off or dim at set times or under set conditions. Facilities managers can make changes to lighting when appropriate or to meet financial incentives, and users can have control over their own lighting levels to provide optimal working conditions. Lighting control helps to reduce costs and conserve energy by turning off (or dimming) lights when they are not required. Energy savings resulting from daylight harvesting mean not only low electric lighting and reduced peak electrical demands, but also reduction in the load on the air conditioner. On the other hand thermal and visual comforts play a very important role regarding the satisfaction of occupants with their working environments. The most effective method to achieve thermal comfort in offices is to reduce cooling loads in order to avoid additional energy-consuming devices for cooling. Most daylight responsive lighting control systems save energy by reducing lamps output in proportion to the amount of available daylight while maintaining a given illuminance level on the working plane. In this paper, variation of room illuminance with daylight along with variation in room temperature is studied. It is proposed to reduce the total electrical load in a general office. 

05/00802 An ideal window area concept for energy efficient integration of daylight and artificial light in buildings

Theoretical evidence is presented on the possibility that proper window sizing as well as proper selection of external surface to volume ratio can result in total energy savings for heating, cooling and lighting in the periphery zones of buildings. The savings are of the order of 50% relative to the windowless configuration. The optimum window are ranges from 10% to 40% of the wall area depending on the size and geometry of the spaces. The calculations were carried out for Austin, Texas using hourly weather data averaged over a 9 year period. The results of the calculations are strongly dependent on the sky illumination calculations. A model of the sky illumination that calculates the perceived intensity of illumination as a function of weather conditions and the orientation of the receptor relative to the sun is developed and the results of an empirical test run on the model are included.

An Ideal Window Area concept for energy efficient integration of daylight and artificial light in buildings

There have been many developments in energy efficiency in buildings in the last few decades, but many new buildings are still not designed whereby daylight is efficiently integrated with the artificial lighting system. In cases where there is integration, the potential for energy savings to be made on lighting is not always assessed. This paper presents a methodology to predict the potential for energy savings on lighting using an Ideal Window Area concept when there is effective daylight integration with the artificial lighting system. The methodology was developed by using rooms of ten different dimensions and five different room ratios. The energy analysis work was performed using the VisualDOE programme for the climatic conditions of Leeds, in the UK, and Florianópolis, in Brazil. Following this, the potential for lighting energy savings was assessed for each room using a method based on Daylight Factors. It was observed that the potential for energy savings on lighting in Leeds ranged from 10.8% to 44.0% over all room sizes and room ratios for an external illuminance of 5000 lux ; and in Florianópolis, the potential ranged between 20.6% and 86.2% for an external illuminance of 10000 lux . The methodology presented can be applied to any location around the world.