Standardizing Melanopic Effects of Ocular Light for Ecological Lighting Design of Nonresidential Buildings—An Overview of Current Legislation and Accompanying Scientific Studies

The Future of Interior Lighting Is Here

One word that characterizes the situation in the lighting industry during recent years is “change” [...]

Dense and Proximate Development—Daylight in the Downtown Area of a Compact City

Daylight is of utmost importance and should be the main source of light in most areas dedicated to working and living. When considering our contemporary way of living, it can be easily discerned that most of our life is spent indoors, yet in a typical architectonic design approach, daylight is too often hardly of consequence. Hence daylight becomes a critical factor. Designers comply with the legal requirements of the solar hours required for areas subjected to constant use. Simultaneously for electrical engineers’ daylight is only an additional source of light valued only where energy efficiency is concerned. The basic idea of this research is to, starting from the concept level, design the building’s volume in line with energy efficiency requirements and user expectations using daylight access strategy as the main parameter. This scope of research has been a subject of various scientific theses conducted within the last years at the Faculty of Architecture Warsaw University of Technology. This paper is dedicated to the latest and most developed outcomes. The presented solution is an architectonic point of view dedicated to the use of the daylight factor in office areas located in a dense city district that may support efficient energy requirements, including the requirements of the electric lighting system. Illumination values were set according to the BREEAM daylight and PN-EN 17037 Daylight of Buildings standard. The presented strategy is unconventional for Poland, but has the potential to be included in practice and should be developed further, together with electrical engineers, as a part of energy-saving solutions. Possibly, it should be followed simultaneously with the development of the compact cities ideas. It is hoped that it might be a starting point for discussion, and for a more detailed interdisciplinary research in the future.

A Randomized Controlled Trail for Comparing LED Color Temperature and Color Rendering Attributes in Different Illuminance Environments for Human-Centric Office Lighting

In this study, two experiments were conducted to investigate the effects of the color rendering index (CRI) and correlated color temperature (CCT) of light-emitting diode (LED) lighting on office user acceptance and to explore the proper color attributes for human-centric office lighting. Experiment 1 had four LED lights, with two levels for the CRI (CRI < 80: 79, 76; or CRI ≥ 80: 83, 84) and CCT (3000 K or 6500 K) at 300 lux. In experiment 2, there were four LED lights, with several levels for the CRI (CRI < 80: 78; or CRI ≥ 80: 87, 83) and CCT (3000 K or 6500 K) at 500 lux. Ninety-six participants in experiment 1 and ninety-four participants in experiment 2 performed a reading task. The results in experiment 1 and experiment 2 showed that LEDs with lower CRI values at warm color temperatures were rated as more acceptable than LEDs with higher CRI values at warm color temperatures. However, the positive effect extended to LEDs with higher CRI values at cool temperatures but not to LEDs with lower CRI values at cool temperatures. Therefore, the findings are that LEDs with lower CRI values at warm color temperatures and LEDs with higher CRI values at cool temperatures provide the right level of color attributes for office lighting.