Modern buildings are highly glazed and necessitate an enormous amount of energy to maintain thermal and visual comfort. To reduce the energy requirements of such buildings, conventional glazings ...should be replaced by energy-efficient glazing systems. In this paper, the cost-effective insulating material is used in the glazing application. This glazing system is made by filling the crystal mud transparent slime (TS) in the air gap of the conventional double-glazing unit. The solar-optical and colour rendering properties, thermal properties, solar heat gains, yearly net operating costs and cost savings, repayment period, and CO2 emission mitigation of transparent slime glazings with varied gaps, including 4 mm, 8 mm, and 12 mm, were evaluated. These evaluations were made for the Sholapur (hot and dry) and Lucknow (composite) climatic zones of India. This study revealed the potential of TS glazings in reducing the heat gains, net operating costs and CO2 emissions compared to conventional double-glazing units (ADGUs) with 4 mm, 8 mm and 12 mm air gaps. In comparison to conventional air-filled double glazing with a 12 mm gap (ADGU-12), transparent slime glazing with a 12 mm gap (TS-12) has demonstrated the greatest savings in heat gain of 21.3 % and yearly net operating cost of 21.32 %. TS-12 has recorded the highest cost savings of $132.62 and $119.85 for the Sholapur and Lucknow climatic zones respectively. TS-12 obtained the highest CO2 emission mitigation of 2.107 (tCO2/year) for Sholapur climatic conditions. All the TS glazings have shown a very less repayment period ranging from 4.97 to 6.16 years. Daylighting analysis for a dining hall building model with TS glazings revealed adequate natural illumination inside the building. All the TS glazings have shown good colour quality and uniform daylighting. This work gives a novel idea for reducing the energy consumption of buildings.
•A novel crystal mud transparent slime glazing system for buildings•Transparent slime glazing system as a replacement to conventional double glazing systems•Solar optical properties of transparent slime glazing systems•Transparent slime glazing system for reduced annual net cooling and heating costs•Transparent slime glazing system for enhanced daylight factors and useful daylight illuminance
Daylight-inclusive building codes are difficult to establish for rapidly developing dense urban centers in the global south. Obstruction Angle (OA) has long been used as a precursor in ...daylight-inclusive building codes. However, such codes are more suitable for higher latitude cities with low-rise developments but less effective in low latitude dense cities such as Dhaka. Existing research established Unobstructed Vision Area (UVA) as a critical daylight precursor for dense urban developments. This study further established Canyon Wall Porosity (CWP) as another critical daylight precursor and detailed a CWP calculation method. Via OA, UVA, and CWP, this study examined existing Dhaka building codes against optimal values for setbacks, building height limit, Floor Area Ratio (FAR) and Maximum Ground Coverage (MGC). The findings revealed: (a) 63° OA is critical for Dhaka, and it should be used to set setbacks distances and building height limits (b) front setbacks could be narrower as streets assist in sustaining 63° OA, but rear-setbacks should be significantly wider (c) MGC should be lower to achieve high CWP for adequate daylight. These findings, especially the introduction of CWP for daylight inclusivity, could be a catalyst for solar legislation in other mega-urban centers on similar latitudes.
•A maximum Obstruction Angle (OA) of 63o is critical for daylight in dense residential areas of Dhaka city.•While establishing building codes, 63o OA should be considered in determining setback and height limit.•Front setback should be kept narrower as streets help to sustain 63o OA.•Rear setback should be kept significantly wider to have 63o OA.•Higher Canyon Wall Porosity (CWP) helps improving daylight and it increases as MGC decreases.
Daylight dynamic metrics are useful tools for quantifying the switch-on time or the dimming of electric lighting according to the architectural scenario. A variant of these metrics can also be used ...to define strategies to control the lighting fixtures, dimming the luminous flux with no need for external input and reducing therefore the energy consumption of the lighting systems. Given this context, a new approach is proposed, Continuous Overcast Daylight Autonomy (DAo.con), defined as the percentage of occupied time when an illuminance threshold is met by daylight alone under continuous overcast sky conditions, considering a partial credit linearly to values below the threshold defined. This concept acts as an algorithm which adjusts the luminous flux of the luminaires according to the Daylight Factors measured or simulated, considering user requirements and ignoring any internal device for actively measuring the lighting conditions. The Daylight Factors can be modified according to the use of shading devices that affect to the indoor natural light. Accordingly, this algorithm can significantly reduce the embodied cost of the lighting smart controls, promoting their spread and its implementation in building refurbishment, while the energy consumption in electric lighting is reduced by up to 76% for large windows and by up to 65% for medium-sized openings. The results show that the use of this algorithm in office environments with LED fixtures can promote energy savings of up to 7.8 W/m
2
for locations with predominantly clear skies and up to 5.7 W/m
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for northern latitudes with mainly overcast skies.
The aim of this research is to quantify the daylight factors produced inside a room for different models of windows, and to conduct an analysis of the results obtained. All trials were performed ...under overcast sky conditions, as these represent the worst case scenario for calculation. The shape, size and position of the window are variable, as is the reflectance of the inner surfaces of the room. A total of 28 simulations are provided by the lighting simulation program Daylight Visualizer 2.6, validated by the CIE test cases. After trials it was concluded that square windows produce daylight factors slightly higher than those obtained with horizontal windows and noticeably higher than those measured with vertical windows, considering the same surface of openings. It is confirmed that the daylight factors are directly proportional to the glass surface, except in the area near the window. It is also concluded that the windows in the upper position allow higher luminance at the back of the room than those in centered locations. Finally, the energy savings produced by the different models of windows is calculated.
•The windows performance is analyzed according to their shape, size and position.•The quantified daylight factors show a database of daylight produced by a window.•Analysis of results determines the performance of the window variables.•Horizontal windows allow higher energy saving than other window shapes.•Energy saving allowed by the reflectance of the surfaces of a room is quantified.
Conducting a rigorous evaluation of the daylight performance of buildings is essential for human health and energy efficiency. Today, there are two main methods used for analysis: the daylight ...factor, which has been used since the early 1900s, and the newer approach known as climate-based modelling. Both methods are employed in the EN 17037 Daylight in Buildings’ standard. Utilizing different calculation methods causes discrepancies in daylight provision performance analyses of a room. However, there is no definition or limitation for this subject in the standard. As a result, researchers prefer different calculation methods for the same location in daylighting analyses without a clear justification. Additionally, there is a lack of parametric methods that follow the guidelines of the standard. This study aims to analyse the impact of calculation methods on daylighting analyses according to different regions and generate parametric methods in compliance with the standard. In this respect, comparison calculations are conducted for a theoretical room situated in all 81 provinces of Turkey, where variant climate types occur over a year. Furthermore, parametric workflows are generated using Rhinoceros/Grasshopper following the directives of the standard. The findings indicate that the method choice affects the illumination levels in all zones, ranging from 15 to 114 %.
Abstract
Visual information acquisition is essential for our daily lives, with vision relying on the presence of light. Lighting systems serve the fundamental purpose of enabling vision. This study ...aims to contribute to sustainable architectural design by emphasizing the efficient utilization of natural daylight. Specifically, the design of skylights or light wells in low–lateral-area, deep-depth structures is of significant importance. While current design criteria consider skylight dimensions and the skylight-to-building height ratio, these factors alone may not suffice for optimal skylight design. To achieve an appropriate lighting and architectural design for such structures, it is essential to evaluate the factors influencing the required amount of daylight on different floors. This study aims to investigate the impact of skylights and light wells on the energy consumption and CO2 emissions of a four-storey building located in Hail, Kingdom of Saudi Arabia. The physical parameters of skylights and light wells were analyzed, taking into account various aspects that affect the amount of light reaching different levels. The findings highlight the significant influence of skylight size on the light reaching the building’s floors. For square skylights, reducing the well index (increasing skylight size) exponentially increases the daylight factor. Furthermore, this study evaluates the annual energy consumption and carbon dioxide emissions of the building, considering the daylighting factor. The results demonstrate that skylights contribute to increased solar heat gain, thermal conductance, and artificial lighting efficiency. Notably, as the lighting factor of the building increases from 3% to 6%, there is an annual decrease of 3% in CO2 emissions.
The proper design and selection of daylighting systems can significantly help in improving energy efficiency and reducing environmental pollution. The aim of this paper is to review the fundamental ...aspects of daylighting and lighting control strategies, including the daylight factor, illuminance and luminance, and glare index. By itself, daylighting in a building does not lead to energy savings unless it is integrated with artificial lighting systems through lighting control techniques. The daylight factor is still the most commonly used parameter to characterize the daylight situation in a building. To achieve a comfortable brightness balance, it is desirable to limit the luminance ratio between areas of appreciable size as seen from a normal viewing position. The illuminance level and its distribution on the work plane and the surrounding area have a great impact on an occupant’s visual task. Glare is recognized as an important issue in providing visual comfort and must be evaluated and prevented when it occurs within a daylit space. This work is a useful source for architects, building professionals, researchers, and newcomers to gain a better understanding of daylighting fundamental issues to promote effective daylighting designs and systems.
Building glazing systems have a significant impact on air-conditioning loads and diurnal illumination in buildings. Incorporating thermal-insulating materials in the interspace of double-glazing is ...an ideal energy-efficient choice to insulate glazing for reduced air-conditioning costs with comfortable daylight factors. This paper evaluates the solar-optical, color rendering properties, thermal indices, and cost-savings potential of novel glazing systems, where the air-space of double-glazing is filled with different colored hydrogel granules (hydrogel glazing). Thermo-economic analysis was carried out with a numerical model for India's three distinct climatic regions (Warm, Hot, and Temperate). Proposed hydrogel glazing showed a substantial heat gain/loss reduction, resulting in enhanced air-conditioning cost savings. The double glazing with orange hydrogels granules (DGOH) showed a reduction of 31.67% in summer solar heat gains for the temperate climate. The analysis had concluded net annual cost savings of 6.99 $/m
2
for DGOH glazing with a payback period of 0.40 years for the temperate climate. Warm and hot climates also reported identical heat gain reductions and annual savings ($/m
2
). Carbon emission mitigations of building with hydrogel glazing were estimated with the help of yearly carbon emission factors. The simulated average daylight factors of model buildings with hydrogel glazing were well above the recommended levels in compliance with building codes. The assessed color rendering metrics of hydrogel glazings were satisfactory for visual acceptability in building interiors. The results of this work help engineers and architects to decide on energy-efficient glazing systems for energy-conscious buildings.
Buildings with conventional glazing systems are responsible for excessive cooling and heating costs. Sustainable use of energy in building environments requires the use of high-performing opaque and ...windowed walls. Triple glazing units attenuate solar heat gain/loss compared to single- and double-glazing assemblies, thus reducing air-conditioning costs and greenhouse gas emissions. The optical, energy, economic and environmental performances of a glazing unit are strictly correlated with each other. An improvement of optical properties leads to higher glazing energy performance, cost savings, and greenhouse gas emission mitigations. This work aims to suggest and define an energy-efficient triple glazing unit for lowering cooling and heating costs in buildings while experimentally testing the spectral performance of reflective glasses and assessing heat gains/losses. In this regard, bronze, green, grey, sapphire blue, and gold reflective glasses were considered and settled in sixty different triple glazing combinations. Spectral characteristics of reflective glasses were measured experimentally using a spectrophotometer over the entire solar spectral range (300–2500 nm). For the aims of this investigation, a numerical model was developed to assess the net annual cost saving ($/m2) and the payback period of the examined glazing units for the eight cardinal directions (N, N-E, E, S-E, S, S–W, W and N–W). The results confirmed that the TWG35 window glass unit in the S-E orientation was the most energy-efficient glazing in terms of alleviating this critical challenge (air-conditioning cost-saving 16.72 $/m2 among all other studied window glass units), while a payback period of 2.2 years was revealed. On the other hand, the TWG33 window glass unit has led to the optimal-lowest payback period (2.1 years), with a net annual cost saving of 16.55 $/m2. The findings of this paper demonstrate the significance of triple-glazing design approaches from an economic and environmental point of view.
•Reflective triple glazing design strategies for reduced air-conditioning costs.•Diurnal illumination levels through reflective triple glazing systems.•Operational energy and net annual cost savings of reflective triple glazing systems.•Color rendering index and quality of daylight through triple glazing systems.
The indoor climate of industrial buildings is a function of production technology and requirements for the creation of an optimal artificial material environment. Currently, we consider daylight not ...only as a source of illumination, but also as an aesthetic element of a building or a way of reducing energy consumption. Light in a closed space allows a person to obtain basic visual information (perception) and perform visual tasks. Top lighting schemes can provide increasingly more useful illumination from smaller apertures than side lighting when they capture and diffuse sunlight. Sunlight is roughly 10 times brighter than light from the sky or clouds. A combined lighting system (top lighting and side lighting) ensures a better light distribution in industrial buildings. In this study, we present a comparison of daylight factors for different types of skylights. Specifically, a saddle skylight in the hall and three other types of skylights were created and simulated. In all the cases, the models of skylights were prepared and simulated using RADIANCE. Additionally, a comparison of simulation results obtained with RADIANCE was conducted to quantify the lighting climate. Overall, saddle roof was considered as the best choice for daylight in an industrial hall.
