Quantum Dot Photolithography using Quantum Dot Photoresist composed of Organic-Inorganic Hybrid Coating Layer

Quantum dots (QDs) have emerged as an important class of material due to their excellent photonic properties and durability for diverse applications such as solid-state lighting, energy conversion, display, biomedicine,...

Integrating Daylighting with Task-Ambient Lighting for Enhanced Energy Savings in Office Spaces

Daylighting has been widely studied as a fundamental aspect of spatial illumination and energy efficient façade design. Effective installation and control of shading devices diminishes the adverse effects of prevailing climatic conditions on building envelope performance and reduces resultant lighting and cooling energy consumption. Task-ambient lighting as a free-standing approach has also been proven to reduce lighting energy consumption compared with typical general ambient lighting. This study estimates the energy saving potential of integrating daylighting through fixed external horizontal shading slats with task lighting. Spot measurements were taken in a test room to validate a daylight calculation program. Full year indoor work plane daylight simulations were performed for office spaces of different floor areas and varying window to wall ratios. Indoor daylight quality was assessed using the Useful Daylight Illuminance metric and three different task lighting schemes explored. Lighting energy savings of 10% to 90% were estimated under the three schemes in comparison to similar office spaces with common unshaded heat reflective glazing.

Theoretical Impact of Building Façade Thickness on Daylight Metrics and Lighting Energy Demand in Buildings: A Case Study of the Tropics

In daylighting design, variation of building façade thickness (f) will result in variation of the daylight opening areas, which in turn will modify the values of daylight metrics within the space. However, studies dedicated to investigating the impact of varying f on indoor daylight metrics are relatively scarce. This study, therefore, aims to assess the theoretical impact of various façade thicknesses on various daylight metrics and lighting energy demands in a reference office space. Analytical calculations are performed using an outdoor diffuse illuminance profile of a tropical city. The building façade thickness values are varied within 0–0.50 m, at window-to-wall ratios (WWR) of 25%, 50%, and 75%. Based on sensitivity analysis, it is found that variation of f yields different impacts on the observed metrics, with sDA300/50% being the least influenced. Among all metrics in the central calculation point, DA300, UDI-a, and UDI-a′ yield relatively small coefficients of variation, and thus, have the lowest uncertainty with respect to f. Among all metrics for the entire room, sDA300/50% and sUDI-a50% have the lowest uncertainty, with interquartile ranges of no more than 0.4%. Overall, the contribution of this study is providing insight into the impact of façade thickness on various daylight metrics in indoor spaces, particularly in the worst-case scenario under the standard CIE overcast sky.

ANALYSES ON OCCUPANT PATTERNS AND ENERGY CONSUMPTION IN RESIDENTIAL BUILDINGS INCLUDING THE COVID-19 PANDEMIC

In the last years, as a result of environmental concerns, changes in lifestyle during the COVID-19 crisis, the role of healthy buildings in addition to the main lighting design principles are highlighted. Therefore, today’s lighting design issues include social well-being, mental well-being, and physical well-being more than we discussed in the last century. Hence, we are familiar with occupant-centric and performance-based metrics for residential and non-domestic buildings. The study analyses the extended occupancy patterns, daylight availability, and annual lighting energy demand through a case study in Bursa, Turkey including the COVID-19 pandemic scenario.

Determining Proper Daylighting Design Solution for Visual Comfort and Lighting Energy Efficiency: A Case Study for High-Rise Residential Building

Promoting the daylight performance that allows to provide visual comfort conditions by minimizing lighting energy consumption is possible with making a balance of window size, glazing type and shading strategy, which are the major design parameters of the daylighting system. Particularly, in high-rise buildings, where large openings enabling higher daylight availability and view out are preferred, the daylighting system becomes a crucial design consideration in terms of ensuring occupants’ visual comfort and improving lighting energy efficiency. This study aims to identify a proper daylighting design solution with regard to window area, glazing type and shading strategy for a high-rise residential building located in Istanbul considering visual comfort and lighting energy efficiency. The dynamic simulations are carried out by DIVA for Rhino version 4.1.0.12. The results are evaluated with the Daylight Autonomy (DA) to detect daylight availability in the space and Daylight Glare Probability (DGP) to describe the visual comfort conditions related to glare. Furthermore, the lighting energy consumption of each alternative is also analysed to determine the proper daylighting solution. The results have revealed that a proper daylighting solution providing visual comfort by improving lighting energy-efficiency can be determined by the evaluation of the daylight performance both qualitatively and quantitatively.

Optimization of photoluminescent materials for lighting energy saving in the built environment

In the last decades, fossil fuels have become the primary resource for electricity generation, contributing to the aggravation of problems like global warming and ozone depletion. For this reason, innovative solutions are being continuously developed in order to improve energy efficiency in the construction sector. Beyond heating and cooling, urban lighting plays a significant role on the final energy consumption of a city, including both indoors and outdoors. In this work, photoluminescent materials are investigated as possible light sources to be implemented in urban lighting systems, focusing on the free-cost and renewable luminous gain they provide after being exposed to a proper radiation. In particular, commercially available photoluminescent powders are evaluated by means of spectroradiometric techniques and using a specifically designed experimental setup. Measurements are repeated for different intensities and wavebands of irradiation to identify the most promising “pigment-lamp” combination in terms of (i) luminous intensity and (ii) photoluminescence duration. Results show that the shorter the distance between the emission spectra of the exciting source and the photoluminescent powder, the better the performance of the latter. Therefore, the choice of both afterglow and exciting source cannot be independent from the final system’s application and the required end-use lighting level.

The Role of the Internal Heat Gains for Artificial Lighting on the Energy Performance of Buildings

This paper aims to propose a procedure for calculating the energy performance indexes of buildings considering the seasonality of internal gains due to artificial lighting with a monthly quasi-steady-state energy balance. The proposed methodology evaluates the heat gains due to the integrated natural-artificial lighting system with the Lighting Energy Numerical Indicator (LENI). For the evaluation of buildings’ global energy performance and for some energy services, this contribution cannot be considered constant annually as depend strongly by climate conditions. The effect of daylighting, type of light sources-luminaires, building orientation and shading devices could influence lighting contribution of the internal heat gains. Then, the proposed methodology evaluates the internal heat gains with monthly energy balances. This methodology was applied to the case study of the "Brancaccio" retirement home in Matera (IT) for which the values of the energy performance indexes were compared with the standard normative approach using constant internal heat gains. The results of this work underline the importance of performing a detailed analysis that considers the availability of natural light in the different months of the year, the efficiency of the different lighting systems and their power installed per unit of area as a function of the lighting comfort requirements in the different types of environments.

Role of Architectural Design in Creating Circadian-Effective Interior Settings

Daylight variability throughout the day makes it an ideal light source for the stimulation of humans’ circadian systems. However, the key criteria, including proper quantity, quality, and hours of access to daylight, are not always present inside the built environment. Therefore, artificial light is necessary to complement the human’s visual and non-visual needs for light. Architectural design parameters, such as window area, orientation, glazing material, and surface reflectance alter the characteristics of both daylight and artificial light inside buildings. These parameters and their impact on lighting design should be considered from the early design stages to attain a circadian-effective design. In response to this need, a design approach called Human-Centric Lighting (HCL) was introduced. HCL places humans, and their visual and non-visual needs, in the center of the design process. It manipulates the light-related factors, such as spectrum and intensity, within the built environment for circadian benefits. The effect of HCL on lighting energy efficiency is still not clear. This paper reviews essential architectural design parameters and their impacts on circadian lighting design, considers the HCL design process and explores the most widely used circadian lighting metrics and standards.