No abstract

LED lighting products have become a significant revolution in this technological sector. These components are, by nature, digital emitters created with semiconductor crystals that are powered with very low voltage and direct current (DC). Under these conditions, they have become one of the most relevant actors in the present tendency that is recovering the DC as the channel to transport and distribute energy and is reinforcing the photovoltaic (PV) panels as a relevant sustainable energy source that allows to improve the efficiencies of all types of lighting installations with the local self-generated energy. An analysis of the working principles of this component and the mechanism implemented for their control as lighting equipment to be powered with both conventional alternate current (AC) and DC is presented. A specific differentiation is done upon indoor and outdoor applications where new standards and regulations, specific technical procedures, and singular experimental project descriptions are detailed. The results expose the advantages and difficulties of implementation of this new DC paradigm, the main conclusion obtained up to this moment, and trends of future evolution.

Nowadays, LED lighting technology reaches a higher Value of Energy Efficiency in Installations (VEEI) (W/m2*100 lux) than current luminaire lighting due to the number of lumens per watt that these are able to generate, as well as the directional nature of their emissions together with the adjustment capability through concentrator lenses with beam graduations that reach 5º. This achieves energy savings of up to 80%. Furthermore, also considering the substantial decrease in flickers, and that it noticeably improves usage of ultra-slow-motion cameras and the fading of switching-on or rearm times upon failure, LED technology stands out as the main solution for illumination of professional sports facilities. This article describes the evolution of regulatory requirements that are being imposed by the governing institutions of sports (FIFA, UEFA, FIBA, etc.) and professional leagues (LaLiga, Euroliga, etc.) in order to guarantee their competence as high-quality television products. In addition, the trends in requirements and specifications regarding lighting equipment and its installation, which are intended to convert stadiums into optimized centers for the celebration and dissemination of mass events, are analyzed (settings, photometry, etc.), particularly those concerning horizontal, vertical, and camera illuminance, average and extreme uniformities, glare, reduction of intrusive light in bleachers, flickers, color rendering index (CRI), correlated color temperature (CCT), and start-up times.

No abstract

This paper analyzes the technical and economic viability and sustainability of urban street lighting installation projects using equipment powered by photovoltaic (PV) energy. First, a description of the state-of-the-art of the technology is performed, studying the components involved in solar LED luminaires for street lighting application and examples of autonomous PV systems installed in different countries. Later, a case study a based on a renovation project of the street lighting installation at a 5000-inhabitant municipality in Lanzarote (Spain) is presented. Two alternatives are analyzed: underground channeling of the previous aerial electrical grid and the installation of LED luminaires, and, on the other hand, the installation of autonomous LED solar luminaires. Simulations concluded that a PV lighting installation proposal guarantees the existing M3 lighting requirements (EN 13201-2:2015) and represents a saving in the material execution budget of 43.78% with respect to the channeled power grid option. Finally, a statistical study has been carried out to assess the social acceptance of Spanish citizens of this autonomous PV technology in urban environments. This considers strengths and weakness of the technology: sustainability, robustness, visual impact, or risk of vandalism. In general, most subjects of all age segments are aware of the problem that means having aerial wiring running at facades (95%) and considers the use of PV in urban lighting sustainable (88%). However, 47% of those surveyed consider that shutdowns due to lack of energy harvesting is problematic and 17% consider this very problematic. This major drawback (visual impact of PV equipment is mostly evaluated as neutral) gives rise to social reluctance, especially in people younger than 50 who remarked this as more problematic than senior segments. Thus, guaranteed operational service is fundamental to have social agreement for PV technology implementation.